illuminate (v.)
c.1500, "to light up, shine on," a back-formation from illumination, or else from Latin illuminatus, past participle of illuminare (see illumination). Earlier was enlumyen (late 14c.) "decorate written material with gold, silver, bright colors," from Old French enluminer, from Late Latin inluminare; also illumine (late 14c.). Related: Illuminated; illuminating.
illuminati (n.)
1590s, plural of Latin illuminatus "enlightened" (in figurative sense), past participle of illuminare (see illumination). Originally applied to a 16c. Spanish sect (the Alumbrados), then to other sects; since 1797 used as a translation of German Illuminaten, name of a secret society founded 1776 in Ingolstadt, Bavaria, and holding deistic and republican principles; hence used generally of free-thinkers and sarcastically of those professing intellectual enlightenment (1816). Related: Illuminatism; illuminatist.
illumination (n.)
late 14c., "spiritual enlightenment," from Latin illuminationem (nominative illuminatio), from past participle stem of illuminare "to throw into light, make bright, light up;" figuratively "to set off, illustrate," from assimilated form of in- "in, into" (see in- (2)) + lumen (genitive luminis) "light," related to lucere "to shine" (see light (n.)). Meaning "action of lighting" is from 1560s.
illumine (v.)
late 14c., "to enlighten spiritually;" mid-15c., "to light up, shine light on," from Old French illuminer, from Latin illuminare (see illumination). Related: illumined.
illusion (n.)
mid-14c., "act of deception," from Old French illusion "a mocking, deceit, deception" (12c.), from Latin illusionem (nominative illusio) "a mocking, jesting, irony," from illudere "mock at," literally "to play with," from assimilated form of in- "at, upon" (see in- (2)) + ludere "to play" (see ludicrous). Sense of "deceptive appearance" developed in Church Latin and was attested in English by late 14c. Related: Illusioned "full of illusions" (1920).
illusionary (adj.)
1886, from illusion + -ary.
illusionist (n.)
"conjurer, magic act performer," 1840, from illusion + -ist. Earlier "one suffering from illusions" (1812).
illusive (adj.)
"deceptive, illusory," formed in English 1670s, from stem of illusion + -ive. Also see illusory.
illusory (adj.)
1590s, from French illusorie, from Late Latin illusorius "ironical, of a mocking character," from illus-, past participle stem of Latin illudere "mock at," literally "to play with," from assimilated form of in- "at, upon" (see in- (2)) + ludere "to play" (see ludicrous).
illustrate (v.)
1520s, "light up, shed light on;" 1610s, "educate by means of examples," back-formation from illustration, and in some cases from Latin illustratus, past participle of illustrare (see illustration). Sense of "provide pictures to explain or decorate" is 1630s. Related: Illustrated; illustrating.
illustration (n.)
c.1400, "a shining;" early 15c., "a manifestation;" mid-15c., "a spiritual illumination," from Old French illustration "apparition, appearance," and directly from Latin illustrationem (nominative illustratio) "vivid representation" (in writing), literally "an enlightening," from past participle stem of illustrare "light up, make light, illuminate;" figuratively "make clear, disclose, explain; adorn, render distinguished," from assimilated form of in- "in" (see in- (2)) + lustrare "make bright, illuminate," related to lucere "shine," lux "light" (see light (n.)). Mental sense of "act of making clear in the mind" is from 1580s. Meaning "an illustrative picture" is from 1816.
illustrative (adj.)
1640s, from illustrate + -ive.
illustrator (n.)
1590s, "one who enlightens," from illustrate + Latinate agent-noun suffix -or. Meaning "one who draws pictures" is 1680s.
illustrious (adj.)
1560s, from Latin illustris "lighted, bright, brilliant;" figuratively "distinguished, famous," probably a back-formation from illustrare "embellish, distinguish, make famous" (see illustration). Sometimes also illustrous. Replaced illustre in same sense (mid-15c.), from Middle French illustre.
illy (adv.)
"in an ill manner," 1540s, from ill (adj.) + -ly (2).
Illyria
ancient country on the northeast shore of the Adriatic in modern Croatia; the name is of obscure origin.
Ilocano
from Philippine Spanish Ilocos, literally "river men," from Tagalog ilog "river."
im-
variant of in- before -b-, -m-, -p-, in the sense of "not, opposite of" (immobile, impersonal) as well as "in, into" (implant, impoverish). See in-. In some English words it alternates with em- (1).
image (n.)
c.1200, "piece of statuary; artificial representation that looks like a person or thing," from Old French image "image, likeness; figure, drawing, portrait; reflection; statue," earlier imagene (11c.), from Latin imaginem (nominative imago) "copy, statue, picture," figuratively "idea, appearance," from stem of imitari "to copy, imitate" (see imitation).

Meaning "reflection in a mirror" is early 14c. The mental sense was in Latin, and appears in English late 14c. Sense of "public impression" is attested in isolated cases from 1908 but not in common use until its rise in the jargon of advertising and public relations, c.1958.
image (v.)
late 14c., "to form a mental picture," from Old French imagier, from image (see image (n.)). Related: Imaged; imaging.
imagery (n.)
mid-14c., "piece of sculpture, carved figures," from Old French imagerie (13c.), from imagier "painter," from image (see image (n.)). Meaning "ornate description" (in poetry, etc.) is from 1580s.
imaginable (adj.)
late 14c., ymaginable, from Old French imaginable and directly from Late Latin imaginabilis, from Latin imaginari (see imagine). Related: Imaginably.
imaginary (adj.)
"not real," late 14c., ymaginaire, from imagine + -ary; or else from Late Latin imaginarius "seeming, fancied," from imaginari. Imaginary friend (one who does not exist) attested by 1789.
imagination (n.)
"faculty of the mind which forms and manipulates images," mid-14c., ymaginacion, from Old French imaginacion "concept, mental picture; hallucination," from Latin imaginationem (nominative imaginatio) "imagination, a fancy," noun of action from past participle stem of imaginari (see imagine).
imaginative (adj.)
late 14c., ymaginatyf, from Old French imaginatif and directly from Medieval Latin imaginativus, from imaginat-, stem of Latin imaginari (see imagine). Related: Imaginatively; imaginativeness.
imagine (v.)
mid-14c., "to form a mental image of," from Old French imaginer "sculpt, carve, paint; decorate, embellish" (13c.), from Latin imaginari "to form a mental picture to oneself, imagine" (also, in Late Latin imaginare "to form an image of, represent"), from imago (see image). Sense of "suppose" is first recorded late 14c. Related: Imagined; imagining.
imagism (n.)
name of a movement in poetry that sought clarity of expression through use of precise visual images, "hard light, clear edges," coined 1912 by Ezra Pound; see image + -ism. Related: Imagist.
imago (n.)
1797, from Latin imago "image" (see image).
imam (n.)
1610s, from Arabic, literally "leader; one who precedes," from amma "to go before, precede."
imbalance (n.)
1895, from im- "not" + balance (n.).
imbecile (adj.)
1540s, imbecille "weak, feeble" (especially in reference to the body), from Middle French imbecile (15c.), from Latin imbecillus "weak, feeble" (see imbecility). Sense shifted to mental weakness from mid-18c. As a noun, "feeble-minded person," it is attested from 1802. Traditionally an adult with a mental age of roughly 6 to 9 (above an idiot but beneath a moron).
imbecilic (adj.)
1875, from imbecile + -ic.
imbecility (n.)
early 15c., "physical weakness, feebleness (of a body part), impotence," from Middle French imbécillité and directly from Latin imbecillitatem (nominative imbecillitas) "weakness, feebleness," from imbecillus "weak, feeble," traditionally said to mean "unsupported" (quasi sine baculo), from assimilated form of in- "not, opposite of" (see in- (1)) + baculum "a stick" (see bacillus). "Weakness in mind" (as opposed to body) was a secondary sense in Latin but was not attested in English until 1620s.
imbibe (v.)
late 14c., from Old French imbiber, embiber "to soak into," from Latin imbibere "absorb, drink in, inhale," from assimilated form of in- "into, in, on, upon" (see in- (2)) + bibere "to drink," related to potare "to drink," from PIE *po(i)- "to drink" (see potion). Figurative sense of "mentally drink in" (knowledge, ideas, etc.) was the main one in classical Latin, first attested in English 1550s. Related: Imbibed; imbibing.
imbricate (v.)
1704 (implied in imbricated), from Latin imbricatus "covered with tiles," past participle of imbricare "to cover with rain tiles" (see imbrication). As an adjective from 1650s. Related: Imbricated; imbricating.
imbrication (n.)
1640s, from French imbrication, from Latin imbricare "to cover with tiles," from imbricem (nominative imbrex) "curved roof tile used to draw off rain," from imber (genitive imbris) "rain," from PIE *ombh-ro- "rain" (cognates: Sanskrit abhra "cloud, thunder-cloud, rainy weather," Greek ombros "rain"), from root *nebh- "moist, water" (see nebula).
imbroglio (n.)
1750, from Italian imbroglio, from imbrogliare "confuse, tangle," from assimilated form of in- "into, in, on, upon" (see in- (2)) + brogliare "embroil," probably from Middle French brouiller "confuse" (see broil (v.2); also see embroil).
imbrue (v.)
early 15c., "to soak, steep;" mid-15c., "to stain, soil," from Old French embreuvere "to moisten," a metathesis of embeuvrer, from em- (see im-) + -bevrer, ultimately from Latin bibere "to drink" (see imbibe). Or perhaps from Old French embroue "soiled," ultimately from boue "mud, dirt."
imbue (v.)
early 15c., "to keep wet; to soak, saturate;" also figuratively "to cause to absorb" (feelings, opinions, etc.), from Latin imbuere "moisten," of uncertain origin, perhaps from the same root as imbrication. Compare also Old French embu, past participle of emboivre, from Latin imbibere "drink in, soak in" (see imbibe), which might have influenced the English word. Related: Imbued; imbuing.
imburse (v.)
1520s, from Medieval Latin imbursare, from assimilated form of in- "into, in, on, upon" (see in- (2)) + bursa "purse." Related: Imbursement.
imitable (adj.)
from French imitable (16c.), from Latin imitabilis "that may be imitated," from imitari (see imitation). Related: Imitability.
imitate (v.)
1530s, a back-formation from imitation or imitator, or else from Latin imitatus. Related: Imitated; imitating. An Old English word for this was æfterhyrigan.
imitation (n.)
c.1400, "emulation; act of copying," from Old French imitacion, from Latin imitationem (nominative imitatio) "a copying, imitation," from past participle stem of imitari "to copy, portray, imitate," from PIE *im-eto-, from root *aim- "copy" (cognates: Hittite himma- "imitation, substitute"). Meaning "an artificial likeness" is from c.1600. As an adjective, from 1840.
imitative (adj.)
1580s, probably from imitate + -ive; or else from Middle French imitatif, from Late Latin imitativus, from imitat-, stem of imitari.
imitator (n.)
1520s; see imitate + -or. Perhaps from French imitateur (14c.).
immaculacy (n.)
1799; see immaculate + -cy.
immaculate (adj.)
early 15c., "free from mental or moral pollution, pure," from a figurative use of Latin immaculatus "unstained," from assimilated form of in- "not, opposite of" (see in- (1)) + maculatus "spotted, defiled," past participle of maculare "to spot," from macula "spot, blemish." The literal sense of "spotlessly clean or neat" in English is first attested 1735. Immaculate Conception is late 15c., from Middle French conception immaculée (late 15c.); declared to be an article of faith in 1854.
immanence (n.)
1816; see immanent + -ence. Immanency is from 1650s.
immanent (adj.)
"indwelling, inherent," 1530s, via French, from Late Latin immanens, present participle of Latin immanere "to dwell in, remain in," from assimilated form of in- "into, in, on, upon" (see in- (2)) + manere "to dwell" (see manor). Contrasted with transcendent. Related: Immanently.
Immanuel
masc. proper name; see Emmanuel.