Online Etymology Dictionary

imply (v.): late 14c., "to enfold, enwrap, entangle" (the classical Latin sense), from Old French emplier, from Latin implicare "involve" (see implication). Meaning "to involve something unstated as a logical consequence" first recorded c.1400; that of "to hint at" from 1580s. Related: Implied; implying. The distinction between imply and infer is in "What do you imply by that remark?" But, "What am I to infer from that remark?"
impolite (adj.): 1610s, "unrefined, rough," from Latin impolitus "unpolished, rough, unrefined," from assimilated form of in- "not, opposite of" (see in- (1)) + politus "polished" (see polite). Sense of "discourteous, ill-mannered" is from 1739. Related: Impolitely; impoliteness.
impolitic (adj.): "not according to good policy," c.1600, from assimilated form of in- (1) "not, opposite of" + politic.
imponderable (adj.): 1794, "weightless," from assimilated form of in- (1) "not, opposite of" + ponderable (see ponder). Figurative use, "unthinkable," from 1814. Related: Imponderably. As a noun, by 1842.
import (v.): early 15c., "convey information, express, make known, signify," from Latin importare "bring in, convey," from assimilated form of in- "into, in" (see in- (2)) + portare "to carry" (see port (n.1)). Sense of "bring in goods from abroad" first recorded c.1500. Related: Imported; importing.
import (n.): "consequence, importance," 1580s; sense of "that which is imported" is from 1680s; both from import (v.).
importance (n.): c.1500, from Middle French importance or directly from Medieval Latin importantia, from importantem (see important).
important (adj.): mid-15c., from Middle French important and directly from Medieval Latin importantem (nominative importans), present participle of importare "be significant in," from Latin importare "bring in" (see import). Related: Importantly.
importation (n.): c.1600; see import (v.) + -ation.
importunate (adj.): 1520s, from importune + -ate, or else from Medieval Latin importunatus, past participle of importunari. Related: Importunately (mid-15c.).
importune (v.): 1520s, back-formation from importunity, or else from Middle French importuner, from Medieval Latin importunari "to make oneself troublesome," from Latin importunus "unfit, troublesome," originally "having no harbor" (i.e. "difficult to access"), from assimilated form of in- "not, opposite of" (see in- (1)) + portus "harbor" (see port (n.1)). Related: Importuned; importuning. As an adjective from early 15c.
importunity (n.): early 15c., "persistence, insistence; over-eagerness," from Middle French importunité (14c.), from Latin importunitatem (nominative importunitas) "unsuitableness; unmannerliness, incivility," from importunus "unfit, troublesome" (see importune).
impose (v.): late 14c., "to lay (a crime, etc.) to the account of," from Old French imposer "put, place; impute, charge, accuse" (c.1300), from assimilated form of in- "into, in" (see in- (2)) + poser "put, place" (see pose (v.1)). Sense of "to lay on as a burden" first recorded 1580s. Related: Imposed; imposing.
imposing (adj.): "that impresses by appearance or manner," 1786, from present participle of impose (v.). Related: Imposingly.
imposition (n.): late 14c., "the levying of taxes, a tax, duty, tribute," from Old French imposicion "tax, duty; a fixing" (early 14c.), from Latin impositionem (nominative impositio) "a laying on," from imponere "to place upon," from assimilated form of in- "into, in" (see in- (2)) + ponere "to put, place" (see position). Sense of "the act of putting (something) on (something else)" is from 1590s. Meaning "an act or instance of imposing" (on someone) first recorded 1630s (see impose).
impossibility (n.): late 14c., "quality of being impossible," from impossible + -ity; perhaps from or modeled on French impossibilité. Meaning "an impossible thing or occurrence" is from c.1500.
impossible (adj.): late 14c., from Old French impossible, from Latin impossibilis "not possible," from assimilated form of in- "not, opposite of" (see in- (1)) + possibilis (see possible). Related: Impossibly.
impost (n.): "tax, duty," 1560s, from Middle French impost, from Medieval Latin impostum, from neuter of Latin impostus, contracted from impositus, past participle of imponere (see impostor).
impostor (n.): 1580s, from Middle French imposteur (16c.), from Late Latin impostor, agent noun from impostus, collateral form of impositus, past participle of imponere "place upon, impose upon, deceive," from assimilated form of in- "into, in, on, upon" (see in- (2)) + ponere "to put place" (see position).
imposture (n.): "act of willfully deceiving others," 1530s, from Middle French imposture, from Late Latin impostura, from impostus (see impost).
impotence (n.): early 15c., "physical weakness," also "poverty," from Middle French impotence "weakness," from Latin impotentia "lack of control or power," from impotentem (nominative impotens); see impotent. In reference to a want of (male) sexual potency, from c.1500. The figurative senses of the word in Latin were "violence, fury, unbridled passion." Related: Impotency.
impotent (adj.): late 14c., "physically weak, enfeebled, crippled," from Old French impotent "powerless, weak, incapable," from Latin imponentem (nominative impotens) "lacking control, powerless," from assimilated form of in- "not, opposite of" (see in- (1)) + ponentem (nominative potens) "potent" (see potent).

Meaning "having no power to accomplish anything" is from mid-15c.; that of "completely lacking in sexual power" (of males) is from mid-15c. Middle English also had a native term for this: Cunt-beaten (mid-15c.). The figurative sense in Latin was "without self-control, headstrong, violent." Related: Impotently.
impound (v.): early 15c., "to shut up in a pen or pound," from assimilated form of in- "into, in" (see in- (2)) + pound (n.). Originally of cattle seized by law. Related: Impounded; impounding.
impoundment (n.): 1660s; see impound + -ment.
impoverish (v.): early 15c., empoverischen, from Old French empoveriss-, stem of empoverir, from em- + povre "poor" (see poor). Related: Impoverished; impoverishing.
impoverishment (n.): 1550s; see impoverish + -ment.
impracticable (adj.): "incapable of being done," 1670s, from assimilated form of in- (1) "not, opposite of" + practicable. Earlier in a sense of "impassable" (1650s).
impractical (adj.): 1823, from assimilated form of in- (1) "not, opposite of" + practical. Impracticable in the same sense dates from 1670s.
imprecate (v.): 1610s, probably a back-formation from imprecation. Related: Imprecated; imprecating; imprecatory (1580s).
imprecation (n.): mid-15c., "a curse, cursing," from Latin imprecationem (nominative imprecatio), from past participle stem of imprecari "invoke, pray, call down upon," from assimilated form of in- "into, in, within" (see in- (2)) + precari "to pray, ask, beg, request" (see pray). "Current limited sense is characteristic of human nature." [Weekley]
imprecise (adj.): 1805, from assimilated form of in- (1) "not, opposite of" + precise. Related: Imprecisely.
imprecision (n.): 1803, from assimilated form of in- (1) "not, opposite of" + precision.
impregnable (adj.): early 15c., imprenable "impossible to capture," from Middle French imprenable "invulnerable," from assimilated form of in- "not, opposite of" (see in- (1)) + Old French prenable "assailable, vulnerable" (see pregnable). With intrusive -g- 16c., on model of deign, reign, etc. Related: Impregnability.
impregnate (v.): c.1600, from Late Latin impraegnatus "pregnant," past participle of impraegnare "to render pregnant," from assimilated form of in- "into, in" (see in- (2)) + praegnare "make pregnant" (see pregnant). Earlier in same sense was impregn (1530s).
impregnation (n.): late 14c., "making or becoming pregnant," from Old French impregnacion, from Late Latin impregnationem (nominative impregnatio), from impraegnare (see impregnate).
impresario (n.): 1746, from Italian impresario "operatic manager," literally "undertaker (of a business)," from impresa "undertaking," fem. of impreso, past participle of imprendere "undertake," from Vulgar Latin imprendere, from assimilated form of in- "into, in, on, onto" (see in- (2)) + prehendere "to grasp" (see prehensile).
imprescriptible (adj.): "inalienable, not subject to prescription," 1560s, French imprescriptible (16c.) or a native formation from assimilated form of in- (1) "not, opposite of" + Latin praescriptus, past participle of praescribere "to write beforehand" (see prescribe). Usually with right. Alternative imprescribable is attested from 1887.
impress (v.): late 14c., "have a strong effect on the mind or heart," from Latin impressus, past participle of imprimere "press into or upon, stamp," from assimilated form of in- "into, in, on, upon" (see in- (2)) + premere "to press" (see press (v.1)). Literal sense of "to apply with pressure, make a permanent image in, indent, imprint" is from early 15c. in English. Sense of "to levy for military service" is from 1590s, a meaning more from press (v.2). Related: Impressed; impressing.
impress (n.): "act of impressing," also "characteristic mark," 1590s, from impress (v.).
impressed (adj.): early 15c., "pressed or forced upon" (the mind), past participle adjective from impress (v.).
impression (n.): late 14c., "mark produced by pressure," also "image produced in the mind or emotions," from Old French impression "print, stamp; a pressing on the mind," from Latin impressionem (nominative impressio) "onset, attack," figuratively "perception," literally "a pressing into," from imprimere (see impress). Meaning "act or process of indenting" is early 15c.; that of "printing of a number of copies" is from 1570s. Meaning "belief, vague notion" (as in under the impression) is from 1610s.
impressionable (adj.): 1836, formed on French model, from impression + -able. Earlier was impressible (1620s).
impressionism (n.): 1839 as a term in philosophy, from impression + -ism. Specifically with reference to the French art movement from 1882, from impressionist.
impressionist: as a style of painting aiming to represent overall impressions rather than exact details, first attested in English 1876 (adjective and noun), coined in French 1874 by French critic Louis Leroy ("école impressionniste") in a disparaging reference to Monet's sunset painting "Impression, Soleil Levant." Later extended to other arts.
impressionistic (adj.): 1886; see impressionist + -ic.
impressive (adj.): 1570s, "capable of being easily impressed," from impress + -ive. Meaning "capable of making an impression on the mind or senses" is from 1775. Related: Impressively; impressiveness.
impressment (n.): 1796, "act of impressing into service," from impress (v.) + -ment.
imprimatur (n.): 1640, Modern Latin, literally "let it be printed," the formula of a book licenser, third person singular present subjunctive passive of Latin imprimere "to print" (see impress). Originally of state license to print books, later only of Roman Catholic Church.
imprint (v.): late 14c., from Old French empreinter, from empreinte, noun use of fem. past participle of eimpreindre "to impress, imprint," from Vulgar Latin *impremere, from Latin imprimere "to impress, imprint" (see impress). As a noun from mid-15c.
imprison (v.): c.1300, from Old French emprisoner (12c.), from em- "in" (see in- (2)) + prison (see prison). Related: Imprisoned; imprisoning.