inexplicable (adj.) — informal (adj.)

inexplicable (adj.)

early 15c., from Latin inexplicabilis "that cannot be unfolded or disentangled, very intricate," figuratively, "inexplicable," from in- "not, opposite of" (see in- (1)) + explicabilis "that may be explained" (see explicable).ETD inexplicable (adj.).2

As a noun, 1745, "something that cannot be explained;" jocular inexplicables "trousers" is from 1829. Related: Inexplicably; inexplicability.ETD inexplicable (adj.).3

inexplicit (adj.)

1775 (implied in inexplicitly), from in- (1) "not, opposite of" + explicit. Or else from Latin inexplicitus "not to be unfolded; unexplained." Related: Inexplicitly; inexplicitness.ETD inexplicit (adj.).2

inexpressible (adj.)

1620s, from in- (1) "not" + expressible (see express (v.)). Inexpressibles "trousers" is from 1790. Related: Inexpressibly.ETD inexpressible (adj.).2

Inexpressibles is the earliest recorded and thus seems to have begotten the trend: Unmentionables (1806); indispensibles (1820); ineffables (1823); unutterables (1826); innominables (1827); and inexplicables (1829) followed.ETD inexpressible (adj.).3

inexpugnable (adj.)

late 15c., from Old French inexpugnable (14c.) or directly from Latin inexpugnabilis "not to be taken by assault, not to be rooted out, invincible," from in- "not" (see in- (1)) + expugnabilis "assailable," from expugnare (see expugn). Figurative sense, in reference to arguments, etc., is from 1530s.ETD inexpugnable (adj.).2

inexpungible (adj.)

1610s, from in- (1) "not, opposite of" + expungible (see expunge).ETD inexpungible (adj.).2

inextinguishable (adj.)

c. 1500, from in- (2) "not" + extinguishable. Earlier was inextinguible (early 15c.), from Old French inextinguible or directly from Latin inextinguibilis. Related: Inextinguishably; inextinguishability.ETD inextinguishable (adj.).2

inextirpable (adj.)

1620s, from in- (1) "not, opposite of" + extirpable (see extirpate).ETD inextirpable (adj.).2

in extremis

"at the point of death," 16c., Latin, literally "in the farthest reaches," from ablative plural of extremus "extreme" (see extreme (adj.)).ETD in extremis.2

inextricable (adj.)

early 15c., from Latin inextricabilis "that cannot be disentangled," from in- "not, opposite of" (see in- (1)) + extricare "to disentangle" (see extricate). Related: Inextricably; inextricability.ETD inextricable (adj.).2

Inez

fem. proper name, Spanish form of Agnes (q.v.).ETD Inez.2

in facie curiae

"before the court," legal Latin, from ablative of Latin facies "form, face" (see face (n.)). + genitive of curia "court" (see curia).ETD in facie curiae.2

infallibility (n.)

"quality of being incapable of error," 1610s, from Medieval Latin infallibilitas, from infallibilis (see infallible).ETD infallibility (n.).2

infallible (adj.)

"exempt from error in judgment, knowledge, or opinion," early 15c., from Medieval Latin infallibilis, from in- "not, opposite of" (see in- (1)) + Late Latin fallibilis (see fallible). In reference to Popes, attested from 1870, hence infallibilism, the doctrine of this; infallibilist. Related: Infallibly.ETD infallible (adj.).2

infamous (adj.)

a 16c. merger of two Middle English words, with the form of infamous "not well-known" (early 15c.) and the sense of infamis (late 14c.), "of ill repute, famous for badness." Infamous is from Medieval Latin infamosus, from in- "not, opposite of" (see in- (1)) + Latin famosus "celebrated" (see famous). Infamis is from Latin infamis "of ill fame" (see infamy).ETD infamous (adj.).2

Meaning "causing infamy" is from 1550s. As a legal term, "disqualified from certain rights of citizens because of conviction for certain crimes" (late 14c.). The neutral fameless (in the sense original to infamous) is recorded from 1590s. Related: Infamously.ETD infamous (adj.).3

infamy (n.)

early 15c., "public disgrace, dishonor, evil fame," from Old French infamie "dishonor, infamous person" (14c.) and directly from Latin infamia "ill fame, bad repute, dishonor," from infamis "disreputable, notorious, of ill fame," from in- "not, without" (see in- (1)) + fama "reputation" (from PIE root *bha- (2) "to speak, tell, say"). Meaning "quality of being shamefully vile" is from 1510s.ETD infamy (n.).2

An earlier form in Middle English was infame (late 14c.), from Old French infame, an earlier form of infamie. Infame also was the Middle English verb in this set, "brand with infamy," from Old French infamer, from Latin infamare "bring into ill repute, defame," from infamis. The verb has become archaic in English (infamize is attested from 1590s).ETD infamy (n.).3

infancy (n.)

late 14c., "condition of babyhood," also "childhood, youth," from Anglo-French enfaunce and directly from Latin infantia "early childhood," from infantem "young child," literally "one unable to speak" (see infant). Restriction to the earliest months of life is a return to the etymological sense of the word but is a recent development in English. In old legal language it meant "condition of being a minor" and could mean any age up to 21.ETD infancy (n.).2

infant (n.)

late 14c., infant, infaunt, "a child," also especially "child during earliest period of life, a newborn" (sometimes meaning a fetus), from Latin infantem (nominative infans) "young child, babe in arms," noun use of adjective meaning "not able to speak," from in- "not, opposite of" (see in- (1)) + fans, present participle of fari "to speak," from PIE root *bha- (2) "to speak, tell, say." As an adjective in English, 1580s, from the noun.ETD infant (n.).2

The Romans extended the sense of Latin infans to include older children, hence French enfant "child," Italian fanciullo, fanciulla. In English the word formerly also had the wider sense of "child" (commonly reckoned as up to age 7). The common Germanic words for "child" (represented in English by bairn and child) also are sense extensions of words that originally must have meant "newborn."ETD infant (n.).3

Infanta (n.)

"daughter of a king of Spain or Portugal," c. 1600, from Spanish and Portuguese infanta, fem. of infante "a youth; a prince of royal blood," from Latin infantem (see infant).ETD Infanta (n.).2

infanticide (n.)

1650s, "the killing of infants," especially the killing of newborns or the unborn; 1670s, "one who kills an infant," from infant + -cide. Perhaps from French infanticide (16c.).ETD infanticide (n.).2

infantile (adj.)

mid-15c., "pertaining to infants," from Late Latin infantilis "pertaining to an infant," from infans "young child" (see infant). Sense of "infant-like" is from 1772.ETD infantile (adj.).2

infantilism (n.)

1894 in the psychological sense; see infantile + -ism. Earlier in a physiological sense, "retarded and imperfect physical development," perhaps from French infantilisme (1871).ETD infantilism (n.).2

infantry (n.)

1570s, from French infantrie, infanterie (16c.), from older Italian or Spanish infanteria "foot soldiers, force composed of those too inexperienced or low in rank to be cavalry," a collective noun from infante "foot soldier," originally "a youth," from Latin infantem (see infant). Meaning "infants collectively" is recorded from 1610s. A Middle English (c. 1200) word for "foot-soldiers" was going-folc, literally "going-folk."ETD infantry (n.).2

infantryman (n.)

1837, from infantry + man (n.).ETD infantryman (n.).2

infarction (n.)

1680s, noun of action from Latin infarcire "to stuff into," from in- "into" (from PIE root *en "in") + farcire "to stuff" (see farce).ETD infarction (n.).2

infarct (n.)

substance of an infarction, 1873, from medical Latin infarctus (variant of infartus), past participle of infarcire "to stuff into" (see infarction).ETD infarct (n.).2

infatigable (adj.)

"untiring," c. 1500, from French infatigable (15c.) or directly from Late Latin infatigabilis "that cannot be wearied," from in- "not, opposite of" (see in- (1)) + fatigabilis "that may be wearied," from Latin fatigare "to weary" (see fatigue (n.)).ETD infatigable (adj.).2

infatuation (n.)

1640s, noun of action from infatuate (q.v.), or else from French infatuation or directly from Late Latin infatuationem (nominative infatuatio), from past participle stem of Latin infatuare "make a fool of."ETD infatuation (n.).2

infatuate (v.)

1530s, "turn (something) to foolishness, frustrate by making foolish," from Latin infatuatus, past participle of infatuare "make a fool of," from in- "in" (from PIE root *en "in") + fatuus "foolish" (see fatuous). Specific sense of "inspire (in someone) a foolish passion beyond control of reason" is from 1620s. Related: Infatuated; infatuating.ETD infatuate (v.).2

infeasibility (n.)

1650s, from infeasible + -ity.ETD infeasibility (n.).2

infeasible (adj.)

1530s, from in- (1) "not, opposite of" + feasible.ETD infeasible (adj.).2

infective (adj.)

"infectious, communicable by infection," late 14c., from Latin infectivus, from infect-, past participle stem of inficere "to tinge, dye; stain, spoil" (see infect).ETD infective (adj.).2

infect (v.)

late 14c., "fill with disease, render pestilential; pollute, contaminate; to corrupt morally," from Latin infectus, past participle of inficere "to stain, tinge, dye," also "to corrupt, stain, spoil," literally "to put in to, dip into," from in- "in" (from PIE root *en "in") + facere "to make, do, perform" (from PIE root *dhe- "to set, put"). In Middle English occasionally in a neutral sense "tinge, darken," but typically used of things indifferent or bad, and especially of disease. Related: Infected; infecting.ETD infect (v.).2

infection (n.)

late 14c., "infectious disease; contaminated condition;" from Old French infeccion "contamination, poisoning" (13c.) and directly from Late Latin infectionem (nominative infectio) "infection, contagion," noun of action from past participle stem of Latin inficere "to spoil, to stain" (see infect). Meaning "communication of disease by agency of air or water" (distinguished from contagion, which is body-to-body communication), is from 1540s.ETD infection (n.).2

infectious (adj.)

"catching, having the quality of spreading from person to person, communicable by infection," 1540s of diseases, 1610s of emotions, actions, etc.; see infection + -ous. Earlier in the same sense were infectuous (late 15c.), infective (late 14c.). Related: Infectiously; infectiousness.ETD infectious (adj.).2

infecund (adj.)

early 15c., from Latin infecundus, from in- "not, opposite of" (see in- (1)) + fecundus (see fecund). Related: Infecundity.ETD infecund (adj.).2

infelicity (n.)

late 14c., "unhappiness," from Latin infelicitas "bad luck, misfortune, unhappiness," from infelix (genitive infelicis) "unfruitful, barren; unfortunate, unhappy; causing misfortune, unlucky," from in- "not, opposite of" (see in- (1)) + felix "happy" (see felicity). Meaning "inappropriateness, unhappiness as to occasion" is from 1610s.ETD infelicity (n.).2

infelicitous (adj.)

"unhappy, unlucky," 1754, from in- (1) "not, opposite of" + felicitous. Earlier was infelicious (1590s). Related: infelicitously; infelicitousness.ETD infelicitous (adj.).2

infer (v.)

in logic, "to 'bring in' as a conclusion of a process of reasoning," 1520s, from Latin inferre "bring into, carry in; deduce, infer, conclude, draw an inference; bring against," from in- "in" (from PIE root *en "in") + ferre "to carry, to bear," from PIE root *bher- (1) "to carry; to bear children." General sense of "draw a conclusion" is first attested 1520s; intransitive sense is from 1570s.ETD infer (v.).2

inference (n.)

1590s, "action of inferring;" 1610s, "that which is inferred;" from Medieval Latin inferentia, from Latin inferentem (nominative inferens), present participle of inferre "bring into; conclude, deduce" (see infer).ETD inference (n.).2

inferential (adj.)

1650s, from Medieval Latin inferentia (see inference) + -al (1). Related: Inferentially.ETD inferential (adj.).2

inferior (adj.)

early 15c., of land, "low, lower down, lower in position," from Latin inferior "lower, farther down" (also used figuratively), comparative of inferus (adj.) "that is below or beneath," from infra "below" (see infra-). Meaning "lower in degree, rank, grade, or importance" is from 1530s; absolutely, "of low quality or rank," also from 1530s.ETD inferior (adj.).2

inferior (n.)

"person inferior to another in rank, etc.," early 15c., from inferior (adj.).ETD inferior (n.).2

inferiority (n.)

"state of being inferior," 1590s, probably from Medieval Latin *inferioritas; see inferior + -ity. Inferiority complex first attested 1919.ETD inferiority (n.).2

infernal (adj.)

late 14c., "of or pertaining to the underworld," (ancient Tartarus, the sunless abode of the dead, or the Christian Hell), from Old French enfernal, infernal "of Hell, hellish" (12c.), from Late Latin infernalis "of or belonging to the lower regions," from infernus "hell" (Ambrose), in classical Latin "the lower (world)," noun use of infernus "lower, lying beneath, underground, of the lower regions," from infra "below" (see infra-).ETD infernal (adj.).2

Pluto was infernus rex, and Latin inferi meant "the inhabitants of the infernal regions, the dead." Association of the word with fire and heat is via the Christian conception of Hell. Meaning "devilish, hateful" is from early 15c.; meaning "suitable for or appropriate to Hell" is from c. 1600. As a name of Hell, or a word for things which resemble it, the Italian form inferno has been used in English since 1834, via Dante. Related: Infernally.ETD infernal (adj.).3

inferno (n.)

1834, "Hell, the infernal regions," from Italian inferno, from Late Latin infernus "Hell," in classical Latin "the lower world" (see infernal). As "a large, raging fire" from 1928.ETD inferno (n.).2

infertile (adj.)

1590s, from French infertile (15c.), from Late Latin infertilis "unfruitful," from in- "not, opposite of" (see in- (1)) + Latin fertilis "fruitful, productive" (see fertile).ETD infertile (adj.).2

infertility (n.)

c. 1600, from French infertilité (16c.) or directly from Late Latin infertilitatem (nominative infertilitas), from infertilis "not fertile, unfruitful" (see infertile).ETD infertility (n.).2

infestation (n.)

early 15c., "a being infested," from Old French infestacion, from Late Latin infestationem (nominative infestatio) "a troubling, a disturbing, a molesting," noun of action from past participle stem of Latin infestare "to attack, disturb" (see infest).ETD infestation (n.).2

infest (v.)

late 15c., "to attack, assail, hurt, distress, annoy," from Old French infester (14c.), from Latin infestare "to attack, disturb, trouble," from infestus "unsafe, hostile, threatening, dangerous," originally "inexorable, not able to be handled," from in- "not, opposite of" (see in- (1)) + -festus, perhaps "(able to be) seized" (see manifest (adj.)). Sense of "swarm over in large numbers, attack parasitically" first recorded c. 1600. Related: Infested; infesting.ETD infest (v.).2

infibulation (n.)

1640s, noun of action from infibulate (q.v.); perhaps from or modeled on French infibulation or Medieval Latin *infibulatio.ETD infibulation (n.).2

infibulate (v.)

"to clasp, confine with a buckle, ring, clasp, or the like," especially of the sexual organs, to prevent copulation, 1620s, from Latin infibulatus, past participle of infibulare "to close with a clasp," from in- "on" (from PIE root *en "in") + fibula "a clasp, pin" (from PIE root *dheigw- "to stick, fix"). Related: Infibulated.ETD infibulate (v.).2

infidelity (n.)

c. 1400, "want of faith, unbelief in religion; false belief, paganism;" also (early 15c.) "unfaithfulness or disloyalty to a person" (originally to a sovereign, by 16c. to a lover or spouse), from French infidélité (12c.) or directly from Latin infidelitatem (nominative infidelitas) "unfaithfulness, faithlessness," noun of quality from infidelis "unfaithful, unbelieving" (see infidel).ETD infidelity (n.).2

infidel (n.)

mid-15c., "adherent of a religion opposed to Christianity," from Old French infidèle, from Latin infidelis "unfaithful, not to be trusted," in Late Latin "unbelieving" (in Medieval Latin also as a noun, "unbeliever"), from in- "not, opposite of" (see in- (1)) + fidelis "faithful" (from PIE root *bheidh- "to trust, confide, persuade").ETD infidel (n.).2

Originally "a non-Christian" (especially a Saracen); later "one who does not believe in religion, disbeliever in religion generally" (1520s). Also used to translate Arabic qafir (see Kaffir), which is from a root meaning "to disbelieve, to deny," strictly referring to all non-Muslims but virtually synonymous with "Christian;" hence, from a Muslim or Jewish point of view, "a Christian" (1530s). As an adjective from mid-15c., "of a religion opposed to Christianity;" 1520s as "rejecting the Christian religion while accepting no other."ETD infidel (n.).3

infield (n.)

1733, "land of a farm which lies nearest the homestead," from in (adv.) + field (n.). Baseball diamond sense first attested 1866. Related: Infielder (1867).ETD infield (n.).2

in fieri

legal Latin, "in the process of being done," from fieri "to come into being, become," used as passive of facere "to make, do" (from PIE root *dhe- "to set, put").ETD in fieri.2

in-fighting (n.)

1816, in pugilism, the practice of getting at close quarters with an opponent; see in + fighting. Old English infiht (n.) meant "brawl within a house or between members of a household." Middle English had infight (v.) "to attack" (c. 1300); the modern verb infight "fight at close quarters" (1916) appears to be a back-formation from in-fighting. Related: In-fighter (1812).ETD in-fighting (n.).2

infiltration (n.)

"action or process of infiltrating," in physics, 1796, noun of action from infiltrate. Figurative sense of "a passing into" (anything immaterial) is from 1840; military sense of "stealthy penetration of enemy lines" dates from 1930. The same word had been used earlier in a medical sense of "a knitting together" (early 15c.), from Medieval Latin infiltratio.ETD infiltration (n.).2

infiltrate (v.)

1758, of fluids, from in- (2) "in" + filtrate (v.). Perhaps modeled on French infiltrer (16c.). Military sense of "penetrate enemy lines" attested from 1934. Related: Infiltrated; infiltrating.ETD infiltrate (v.).2

infinity (n.)

late 14c., from Old French infinité "infinity; very large number or quantity" (13c.), from Latin infinitatem (nominative infinitas) "boundlessness, endlessness," from infinitus boundless, unlimited" (see infinite). Latin infinitas was used as a loan-translation of Greek apeiria "infinity," from apeiros "endless."ETD infinity (n.).2

infinitely (adv.)

early 15c., from infinite + -ly (2).ETD infinitely (adv.).2

infinitive (n.)

"simple, uninflected form of a verb, expressing its general sense," 1510s, from earlier use as an adjective (mid-15c.), from Late Latin infinitivus "unlimited, indefinite," from Latin infinitus "not limited" (see infinite). "Indefinite" because not restricted by person or number. Related: Infinitival; infinitively.ETD infinitive (n.).2

infinite (adj.)

late 14c., "eternal, limitless," also "extremely great in number," from Old French infinit "endless, boundless" and directly from Latin infinitus "unbounded, unlimited, countless, numberless," from in- "not, opposite of" (see in- (1)) + finitus "defining, definite," from finis "end" (see finish (v.)). The noun meaning "that which is infinite" is from 1580s.ETD infinite (adj.).2

infinitesimal (adj.)

1710 (1650s as a noun), "infinitely small, less than any assignable quantity," from Modern Latin infinitesimus, from Latin infinitus "infinite" (see infinite) + ordinal word-forming element -esimus, as in centesimus "hundredth." Related: Infinitesimally.ETD infinitesimal (adj.).2

infinitude (n.)

1640s, from Medieval Latin *infinitudo, from Latin infinitus (see infinite) on model of multitudo, magnitudo. Or the English word is perhaps from or modeled on French infinitude (1610s).ETD infinitude (n.).2

infirm (adj.)

late 14c., "weak, unsound" (of things), from Latin infirmus "weak, frail, feeble, not strong or firm" (figuratively "superstitious, pusillanimous, inconstant"), from in- "not, opposite of" (see in- (1)) + firmus "strong; stable," figuratively "constant, trusty" (from suffixed form of PIE root *dher- "to hold firmly, support" ). Of persons, "not strong, unhealthy," first recorded c. 1600. As a noun from 1711.ETD infirm (adj.).2

infirmity (n.)

late 14c., infirmite, "disease, sickness; lack of capability, weakness," from Old French infirmité, enfermete "illness, sickness, disease; moral weakness," and directly from Latin infirmitatem (nominative infirmitas) "want of strength, weakness, feebleness," also "the weaker sex" [Lewis], noun of quality from infirmus "weak, frail" (see infirm).ETD infirmity (n.).2

infirmary (n.)

mid-15c., "sick bay in a monastery," formerly also enfermerie, also firmary, fermery, from Old French enfermerie "hospital" and directly from Medieval Latin infirmaria "a place for the infirm," from Latin infirmus "weak, frail," (see infirm). According to OED, the common name for a public hospital in 18c. England.ETD infirmary (n.).2

inflame (v.)

mid-14c., "make (someone) ardent; set (the spirit, etc.) on fire" with a passion or religious virtue, a figurative sense, from Old French enflamer "catch fire; set on fire" (Modern French enflammer), from Latin inflammare "to set on fire, kindle," figuratively "to rouse, excite," from in- "in" (from PIE root *en "in") + flammare "to flame," from flamma "a flame" (see flame (n.)).ETD inflame (v.).2

The literal sense of "to cause to burn" first recorded in English late 14c. Meaning "to heat, make hot, cause inflammation" is from 1520s. Formerly also enflame, but since 16c. the spelling with in- has predominated. Related: Inflamed; Inflaming.ETD inflame (v.).3

inflammation (n.)

early 15c., in pathology, "excessive redness or swelling in a body part," from Old French inflammation (14c.) and directly from Latin inflammationem (nominative inflammatio) "a kindling, a setting on fire," noun of action from past participle stem of inflammare "to set on fire" (see inflame). Literal sense "act of setting on fire" in English is from 1560s.ETD inflammation (n.).2

inflammable (adj.)

"able to be set alight," c. 1600, from French inflammable, from Medieval Latin inflammabilis, from Latin inflammare "to set on fire" (see inflame).Since 1980s use of the word, especially in safety warnings, has been sometimes discouraged for fear it could be misunderstood as meaning "non-flammable" through confusion of the two prefixes in-. The word was used earlier in medicine in the sense "liable to inflammation" (early 15c.). Related: Inflammability.ETD inflammable (adj.).2

inflammatory (adj.)

"tending to rouse passions or desires," 1711, a figurative use from Latin inflammat-, past participle stem of inflammare "to set on fire" (see inflame) + -ory. From 1732 in pathology, "accompanied by (pathological) inflammation." as a noun from 1680s.ETD inflammatory (adj.).2

inflation (n.)

mid-14c., "swelling caused by gathering of 'wind' in the body; flatulence," also, figuratively, "outbursts of pride," from Latin inflationem (nominative inflatio) "a puffing up, a blowing into; flatulence," noun of action from past-participle stem of inflare "blow into, puff up," figuratively "inspire, encourage," from in- "into" (from PIE root *en "in") + flare "to blow" (according to Watkins from PIE root *bhle- "to blow").ETD inflation (n.).2

The meaning "action of inflating with air or gas" is from c. 1600. The monetary sense of "enlargement of prices" (originally by an increase in the amount of money in circulation) first recorded 1838 in American English.ETD inflation (n.).3

inflate (v.)

early 15c., "cause to swell," from Latin inflatus (source also of Italian enfiare, Spanish inflar, French enfler), past participle of inflare "blow into, puff up," figuratively "inspire, encourage," from in- "into" (from PIE root *en "in") + flare "to blow" (according to Watkins from PIE root *bhle- "to blow"). Economics sense (of prices, currency, etc.) is from 1843. In some senses a back-formation from inflation. Related: Inflated; inflating.ETD inflate (v.).2

inflatable (adj.)

1821, from inflate + -able.ETD inflatable (adj.).2

inflationary (adj.)

1916, from inflation + -ary.ETD inflationary (adj.).2

inflected (adj.)

1640s, "bent, curved," past-participle adjective from inflect (v.). Grammatical sense is from 1775.ETD inflected (adj.).2

inflection (n.)

also inflexion, early 15c., from Latin inflexionem (nominative inflexio) "a bending, inflection, modification," noun of action from past participle stem of inflectere "to bend in, to change" (see inflect). For spelling, see connection. Grammatical sense "variation by declension or conjugation" is from 1660s; pronunciation sense "modulation of the voice" is from c. 1600.ETD inflection (n.).2

inflect (v.)

early 15c., "to bend inward," from Latin inflectere (past participle inflexus) "to bend in, bow, curve," figuratively, "to change, alter, influence," from in- "in" (see in- (1)) + flectere "to bend" (see flexible). Grammatical sense "to vary by change of form" (especially at the end of a word) is from 1660s. Related: Inflected; inflecting.ETD inflect (v.).2

inflexibility (n.)

1610s, from inflexible + -ity.ETD inflexibility (n.).2

inflexible (adj.)

late 14c., "incapable of being bent, physically rigid," also figuratively, "unyielding in temper or purpose," from Old French inflexible and directly from Latin inflexibilis "that cannot be bent," from in- "not, opposite of" (see in- (1)) + flexibilis "pliant, yielding" (see flexible). In early 15c. an identical word had an opposite sense, "capable of being swayed or moved," from the other in- "in, on" (see in- (2)). Related: Inflexibly.ETD inflexible (adj.).2

inflexion (n.)

see inflection; also see -xion. Related: Inflexional.ETD inflexion (n.).2

infliction (n.)

1530s, "act of inflicting;" 1580s, "that which is inflicted," from French infliction (15c.), or directly from Late Latin inflictionem (nominative inflictio) "an inflicting, a striking against," noun of action from past-participle stem of Latin infligere "to strike or dash against" (see inflict).ETD infliction (n.).2

inflict (v.)

1560s, "assail, trouble;" 1590s, "lay or impose as something that must be suffered," from Latin inflictus, past participle of infligere "to strike or dash against; inflict," from in- "in" (from PIE root *en "in") + fligere (past participle flictus) "to dash, strike" (see afflict). You inflict trouble on someone; you afflict someone with trouble. Shame on you.ETD inflict (v.).2

in-flight (adj.)

also inflight, "during or within a flight," 1945, from in (prep.) + flight.ETD in-flight (adj.).2

inflorescence (n.)

1760, "arrangement of flowers on a stem in relation to one another," from Modern Latin inflorescentia, from Late Latin inflorescentem (nominative inflorescens) "flowering," present participle of Latin inflorescere "to come to flower," from in- "in" (from PIE root *en "in") + florescere "to begin to bloom" (see flourish (v.)). Meaning "a beginning to bloom" in English is from 1800.ETD inflorescence (n.).2

inflow (n.)

"act of flowing in or into; that which flows in, influx," 1839, from in (adj.) + flow (n.).ETD inflow (n.).2

influence (n.)

late 14c., an astrological term, "streaming ethereal power from the stars when in certain positions, acting upon character or destiny of men," from Old French influence "emanation from the stars that acts upon one's character and destiny" (13c.), also "a flow of water, a flowing in," from Medieval Latin influentia "a flowing in" (also used in the astrological sense), from Latin influentem (nominative influens), present participle of influere "to flow into, stream in, pour in," from in- "into, in, on, upon" (from PIE root *en "in") + fluere "to flow" (see fluent).ETD influence (n.).2

The range of senses in Middle English was non-personal, in reference to any outflowing of energy that produces effect, of fluid or vaporous substance as well as immaterial or unobservable forces. Meaning "exertion of unseen influence by persons" is from 1580s (a sense already in Medieval Latin, for instance Aquinas); meaning "capacity for producing effects by insensible or invisible means" is from 1650s. Under the influence (of alcohol, etc.) "drunk" first attested 1866.ETD influence (n.).3

influence (v.)

1650s, from influence (n.). Related: Influenced; influencing.ETD influence (v.).2

influent (adj.)

mid-15c., "abundant, flowing in," in reference to occult power of the stars, etc., also of grace, from Latin influentem (nominative influens) "flowing in," present participle of influere "to flow in" (see influence (n.)). Also occasionally in the sense "influential" (1630s).ETD influent (adj.).2

influential (adj.)

"powerful, having influence," 1650s, from Medieval Latin influentialis, from influentia (see influence (n.)). Earlier in an astrological sense (1560s). Related: Influentially.ETD influential (adj.).2

influenza (n.)

type of infectious disease, now known to be caused by a virus, usually occurring as an epidemic, with symptoms similar to a severe cold along with high fever and rapid prostration, 1743, borrowed (during an outbreak of the disease in Europe), from Italian influenza "influenza, epidemic," originally "visitation, influence (of the stars)," from Medieval Latin influentia in the astrological sense (see influence).ETD influenza (n.).2

Used in Italian for diseases at least since 1504 (as in influenza di febbre scarlattina "scarlet fever") on notion of astral, occult, or atmospheric influence. The 1743 outbreak began in Italy. Often applied since mid-19c. to severe colds. For the sense development, compare Latin sideratio "blast, blight, palsy," from siderari "to be planet-struck, afflicted as if by an evil star."ETD influenza (n.).3

influx (n.)

1620s, from French influx (16c.) or directly from Late Latin influxus "a flowing in," from past participle stem of Latin influere "to flow in" (see influence (n.)). Originally of rivers, air, light, spiritual light, etc.; used of people from 1650s.ETD influx (n.).2

info (n.)

1906, short for information.ETD info (n.).2

info-

word-forming element abstracted from information.ETD info-.2

infold (n.)

see enfold. Related: Infolded; infolding.ETD infold (n.).2

infomercial (n.)

1983, from info- + commercial (n.). Before the televised infomercial was the newspaper advertorial (1961).ETD infomercial (n.).2

inform (v.)

early 14c., "to train or instruct in some specific subject," from Old French informer, enformer "instruct, teach" (13c.) and directly from Latin informare "to shape, give form to, delineate," figuratively "train, instruct, educate," from in- "into" (from PIE root *en "in") + formare "to form, shape," from forma "form" (see form (n.)). In early use also enform until c. 1600. Sense of "report facts or news, communicate information to" first recorded late 14c. Related: Informed; informing.ETD inform (v.).2

informant (n.)

1690s, "someone who supplies information," from Latin informantem (nominative informans), present participle of informare "train, instruct, educate" (see inform). Occasionally as "one who gives information to the authorities, one who dishonorably betrays knowledge gained in confidence" (1783). Informer is older in both senses and more usual in the latter. As an adjective from 1890.ETD informant (n.).2

informational (adj.)

1810, from information + -al (1).ETD informational (adj.).2

informative (adj.)

1650s, "instructive, didactic," from Medieval Latin informativus, from Latin informatus, past participle of informare "to train, instruct, educate" (see inform). In Middle English, the same word meant "formative, shaping, plastic, having power to form or animate" (late 14c.). Related: Informatively.ETD informative (adj.).2

informal (adj.)

mid-15c., "lacking form; not in accordance with the rules of formal logic," from in- (1) "not, opposite of" + formal (adj.). Meaning "irregular, unofficial, not according to rule or custom" is from c. 1600. Sense of "done without ceremony" is from 1828. Related: Informally.ETD informal (adj.).2