Online Etymology Dictionary

incise (v.): 1540s, from French inciser (15c.), from Old French enciser (12c.), from Latin incisus, past participle of incidere "to cut into, cut through" (see incision). Related: Incised; incising.
incision (n.): late 14c., "a cutting made in surgery," from Old French incision (13c.) and directly from Latin incisionem (nominative incisio) "a cutting into," noun of action from past participle stem of incidere "to cut in," from in- "into, in, on, upon" (see in- (2)) + -cidere, comb. form of caedere "to cut" (see -cide). Meaning "act of cutting into" is from early 15c.
incisive (adj.): early 15c., inscisif, "slashing, cutting with a sharp edge," from Middle French incisif and directly from Medieval Latin incisivus, from Latin incis-, past participle stem of incidere (see incision). Originally literal; figurative sense of "mentally acute" first recorded 1850 as a borrowing from French. Related: Incisively; incisiveness.
incisor (n.): "cutting tooth," 1670s, from Medieval Latin incisor "a cutting tooth," literally "that which cuts into," from Latin incisus, past participle of incidere (see incision). Inscisours as the name of a cutting tool is attested from early 15c.
incite (v.): mid-15c., from Middle French enciter (14c.), from Latin incitare "to put into rapid motion," figuratively "rouse, urge, encourage, stimulate," from in- "into, in, on, upon" (see in- (2)) + citare "move, excite" (see cite). Related: Incited; inciting.
incitement (n.): 1590s, from incite + -ment.
incitive (adj.): 1888; see incite + -ive.
incivility (n.): 1580s, "want of civilized behavior, rudeness," from French incivilité (early 15c.), from Late Latin incivilitatem (nominative incivilitas), from incivilis "not civil," from in- "not, opposite of" (see in- (1)) + civilis "relating to a citizen, relating to public life, befitting a citizen; popular, affable, courteous" (see civil). Meaning "an act of rudeness" is from 1650s. Incivil "not conducive to common good" is from mid-15c.
inclemency (n.): 1550s, from Middle French inclémence and directly from Latin inclementia "rigor, harshness, roughness," from inclemens (see inclement).
inclement (adj.): 1660s, from French inclément and directly from Latin inclementem (nominative inclemens) "harsh, unmerciful," from in- "not, opposite of, without" (see in- (1)) + clementem "mild, placid." "Limitation to weather is curious" [Weekley].
inclinable (adj.): "amenable, disposed," mid-15c., from Old French enclinable and directly from Latin inclinabilis, from inclinare (see incline).
inclination (n.): "condition of being mentally disposed" (to do something), late 14c., from Middle French inclination (14c.) and directly from Latin inclinationem (nominative inclinatio) "a leaning, bending," figuratively "tendency, bias, favor," noun of action from past participle stem of inclinare (see incline). Meaning "action of bending toward" (something) is from early 15c. That of "amount of a slope" is from 1799.
incline (v.): c.1300, "to bend or bow toward," from Old French encliner, from Latin inclinare "to cause to lean; bend, incline, turn, divert," from in- "into, in, on, upon" (see in- (2)) + clinare "to bend," from PIE *klei-n-, suffixed form of *klei- "to lean" (see lean (v.)). Metaphoric sense of "have a mental disposition toward" is early 15c. in English (but existed in classical Latin). Related: Inclined; inclining.
incline (n.): c.1600, "mental tendency," from incline (v.). The literal meaning "slant, slope" is attested from 1846.
include (v.): c.1400, from Latin includere "to shut in, enclose, imprison, insert," from in- "in" (see in- (2)) + claudere "to shut" (see close (v.)). The alleged Sam Goldwyn-ism, "Include me out," is attested from 1937. Related: Included; including.
inclusion (n.): c.1600, from Latin inclusionem (nominative inclusio) "a shutting up, confinement," noun of action from past participle stem of includere (see include).
inclusive (adj.): mid-15c., from Medieval Latin inclusivus, from Latin inclus-, past participle stem of includere (see include). Related: Inclusively; inclusiveness.
incogitable (adj.): "unthinkable," 1520s, from Late Latin incogitabilis, from in- "not" (see in- (1)) + cogitabilis, from stem of cogitare (see cogitation).
incognito: 1640s, from Italian incognito "unknown," especially in connection with traveling, from Latin incognitus "unknown," from in- "not, opposite of, without" (see in- (1)) + cognitus, past participle of cognoscere "to get to know" (see cognizance). Fem. form incognita was maintained through 19c. by those scrupulous about Latin. Incog was a common 18c. colloquial abbreviation.
incognizant (adj.): 1837, from in- (1) "not, opposite of" + cognizant.
incoherence (n.): 1610s, formed from in- (1) "not" + coherence on model of Italian incoerenza.
incoherency (n.): 1680s, from incoherent + -cy.
incoherent (adj.): 1620s, from in- (1) "not, opposite of" + coherent. Related: Incoherently.
incohesive (adj.): 1826, from in- (1) "not" + cohesive. Related: Incohesively; incohesiveness.
incombustible (adj.): late 15c., from Old French incombustible (14c.) or directly from Medieval Latin incombustibilis; see in- (1) + combustible.
income (n.): c.1300, "entrance, arrival," literally "what enters," perhaps a noun use of the late Old English verb incuman "come in," from in (adv.) + cuman "to come" (see come). Meaning "money made through business or labor" (i.e., "that which 'comes in' as a product of work or business") first recorded c.1600. Income tax is from 1799, first introduced in Britain as a war tax, re-introduced 1842; authorized on a national level in U.S. in 1913.
incoming (n.): late 14c., "action of coming in," from in + coming. As a present participle adjective, from 1753. Of game, from 1892; transferred in World War I to artillery; as a warning cry of incoming shellfire, it seems to date to the U.S. war in Vietnam (1968).
incommensurability (n.): 1560s; see incommensurable + -ity.
incommensurable (adj.): 1550s, from Middle French incommensurable or directly from Medieval Latin incommensurabilis, from in- "not, opposite of, without" (see in- (1)) + Late Latin commensurabilis, from Latin com- "with" + mensurabilis "measurable," from mensurare "to measure" (see measure (v.)). Related: Incommensurably.
incommensurate (adj.): 1640s, from in- (1) "not, opposite of" + commensurate.
incommodious (adj.): 1550s, from in- (1) "not, opposite of" + commodious. Related: Incommodiously. A verb, incommode, is attested from late 16c.
incommodity (n.): early 15c., from Middle French incommodité (late 14c.), from Latin incommoditas, from incommodus, from in- "not" (see in- (1)) + commodus "suitable, convenient" (see commode).
incommunicability (n.): 1630s; see incommunicable + -ity.
incommunicable (adj.): 1560s, "not communicative," from in- (1) "not" + communicable. Sense of "not able to be communicated" first recorded 1570s. Related: Incommunicably.
incommunicado: 1844, American English, from Spanish incomunicado, past participle of incomunicar "deprive of communication," from in- "not" + comunicar "communicate," from Latin communicare "to share, impart" (see communication).
incomparability (n.): c.1500, from incomparable + -ity.
incomparable (adj.): early 15c., from Old French incomparable (12c.) or directly from Latin incomparabilis, from in- "not" (see in- (1)) + comparabilis "comparable" (see comparable).
incomparably (adv.): early 15c., from incomparable + -ly (2).
incompatibility (n.): 1610s; see incompatible + -ity.
incompatible (adj.): mid-15c., from Medieval Latin incompatibilis, from in- "not, opposite of" (see in- (1)) + compatibilis (see compatible). Originally of benefices, "incapable of being held together;" sense of "mutually intolerant" is from 1590s. Related: Incompatibly.
incompetence (n.): 1660s, "inadequacy;" 1716, "want of skill," from French incompétence (mid-16c.), from in- "not, opposite of, without" (see in- (1)) + compétence (see competence). Native formation incompetency (from incompetent + -cy) is attested from 1610s.
incompetency (n.): 1610s; see incompetence.
incompetent (adj.): 1610s, "insufficient," from French incompétent, from Late Latin incompetentem (nominative incompetens) "insufficient," from in- "not" (see in- (1)) + Latin competentem (see competent). Sense of "lacking qualification or ability" first recorded 1630s. The noun meaning "incompetent person" is from 1866. Related: Incompetently.
incomplete (adj.): late 14c., from Latin incompletus "incomplete," from in- "not" (see in- (1)) + completus (see complete).
incompletely (adv.): early 15c., from incomplete + -ly (2).
incompleteness (n.): 1640s; from incomplete + -ness.
incompletion (n.): 1804, noun of action from incomplete.
incomprehensibility (n.): 1640s, from French incompréhensibilité (16c.); see incomprehensible.
incomprehensible (adj.): mid-14c., from Latin incomprehensibilis, from in- "not" (see in- (1)) + comprehensibilis (see comprehensible).
incomprehensibly (adv.): early 15c., from incomprehensible + -ly (2).