Online Etymology Dictionary

institutionalize (v.): "to put into institutional life" (usually deprecatory), 1897; see institution. Earlier (1860) it meant "to make into an institution" and "to adjust to life in an institution" (1893). Related: Institutionalized.
instreaming (adj.): 1855, from in (adv.) + streaming. As a noun from 1876.
instruct (v.): early 15c., "to tell, inform, impart knowledge or information," also "furnish with authoritative directions," from Latin instructus, past participle of instruere "arrange, prepare, set in order; inform, teach," literally "to build, erect," from in- "on" (see in- (2)) + struere "to pile, build" (see structure (n.)). Related: Instructed; instructing.
instructible (adj.): c. 1600, from instruct + -ible.
instruction (n.): c. 1400, instruccioun, "action or process of teaching," from Old French instruccion (14c., Modern French instruction), from Latin instructionem (nominative instructio) "an array, arrangement," in Late Latin "teaching," from past participle stem of instruere "arrange, prepare, set in order; inform, teach," from in- "on" (see in- (2)) + struere "to pile, build" (see structure (n.)).
Teaching is the general word for the imparting of knowledge .... Instruction has the imparting of knowledge for its object, but emphasizes, more than teaching, the employment of orderly arrangement in the things taught. [Century Dictionary]
Meaning "an authoritative direction telling someone what to do; a document giving such directions," is early 15c. Related: Instructions.
instructional (adj.): 1801, from instruction + -al (1).
instructive (adj.): "serving to instruct or inform," 1610s, from instruct (v.) + -ive. An earlier adjective was instructing (1580s). Related: Instructively; instructiveness.
instructor (n.): mid-15c., from Old French instructeur (14c.) and directly from Medieval Latin instructor "teacher" (in classical Latin, "preparer"), agent noun from instruere "arrange; inform, teach" (see instruct).
instrument (n.): late 13c., "musical instrument, mechanical apparatus for producing musical sounds," from Old French instrument, enstrument "means, device; musical instrument" (14c., earlier estrument, 13c.) and directly from Latin instrumentum "a tool, an implement; means, furtherance; apparatus, furniture; ornament, dress, embellishment; a commission, authorization; a document," from instruere "arrange, furnish" (see instruct (v.)). The word in other Germanic languages also is from French.

In English the meaning "a means, an agency" is from mid-14c. The sense of "hand-tool, implement, utensil, something used to produce a mechanical effect" is from early 14c. "Now usually distinguished from a tool, as being used for more delicate work or for artistic or scientific purposes" [OED]. The legal meaning "written document by which formal expression is given to a legal act" is from early 15c. Formerly also used of body parts or organs with special functions.
In wyfhode I wol vse myn Instrument As frely as my makere hath it sent. [Chaucer, "Wife of Bath's Prologue"]
instrumental (adj.): late 14c., "of the nature of an instrument, serving as a means to an end," from Old French instrumental, from Medieval Latin *instrumentalis, from Latin instrumentum "a tool, apparatus" (see instrument (n.)). Meaning "serviceable, useful" is from c. 1600. Of music, c. 1500; noun meaning "musical composition for instruments only" is attested by 1940. Related: Instrumentally; instrumentality.
instrumentalist (n.): "musical performer on an instrument," 1818, from instrumental in the musical sense + -ist. Perhaps from German Instrumentalist (18c.).
instrumentary (adj.): "of or pertaining to a deed or legal instrument," 1722, from instrument (n.) in the legal sense.
instrumentation (n.): "composition and arrangement of music for instruments," 1836, from French instrumentation, from instrument "musical instrument" (see instrument (n.)); also see -ation.
insubordinate (adj.): 1792, on model of French insubordonné (1787); from in- (1) "not, opposite of" + subordinate (adj.) "submitting to authority." Related: Insubordinately.
insubordination (n.): 1790, on the model of French insubordination (1775); from in- (1) "not, opposite of" + subordination.
insubstantial (adj.): c. 1600, from Medieval Latin insubstantialis "not substantial," from in- "not" (see in- (1)) + Late Latin substantialis "having substance or reality, material," in Late Latin "pertaining to the substance or essence," from substantia "being, essence, material" (see substance). Related: Insubstantially.
insubstantiality (n.): 1827, from insubstantial + -ity.
insue (v.): obsolete form of ensue. Related: Insued; insuing.
insufferable (adj.): "intolerable, not to be endured," early 15c., from in- (1) "not, opposite of" + sufferable. Related: Insufferably.
insufficiency (n.): 1520s, from Old French insufficience and directly from Late Latin insufficientia "insufficience," noun of quality from insufficientem "insufficient" (see insufficient). Insufficience "deficiency" is from early 15c.
insufficient (adj.): late 14c., from Old French insufficient (14c.) or directly from Late Latin insufficientem (nominative insufficiens) "not sufficient," from in- "not, opposite of" (see in- (1)) + sufficientem (see sufficient). Originally of persons, "inadequate, unable;" of things, "lacking in what is necessary or required," from late 15c. Related: Insufficiently.
insufflation (n.): 1570s, in ecclesiastical use, "a breathing upon," to symbolize the influence of the Holy Ghost or to expel evil spirits, from Late Latin insufflationem (nominative insufflatio) "a blowing into," noun of action from past participle stem of insufflare, from in- "in, into" (see in- (2)) + sufflare "blow from below," from assimilated form of sub- "under, below" (see sub-) + flare "to blow" (see blow (v.1)). Medical sense of "a blowing of air into" (the lungs) is from 1821; that sense is found earlier in French.
insula (n.): Latin, literally "an island" (also, in ancient Rome, "a block of buildings"); see isle. In anatomical use, the notion is "detached or standing out by itself."
insular (adj.): 1610s, "of or pertaining to an island," from Late Latin insularis "of or belonging to an island," from Latin insula "island" (see isle). Metaphoric sense "narrow, prejudiced" is from 1775, from notion of being isolated and cut off from intercourse with other nations or people (an image that naturally suggested itself in Great Britain). The earlier adjective in the literal sense was insulan (mid-15c.), from Latin insulanus.
insularism (n.): 1828, from insular in the figurative sense + -ism.
insularity (n.): 1755, "narrowness of feelings," from insular in the metaphoric sense + -ity. Sense of "state of being an island" (from the classical sense) attested from 1784, in reference to explorations of Australia and New Zealand.
insulate (v.): 1530s, "make into an island," from Late Latin insulatus "made like an island," from insula "island" (see isle). Sense of "place in an isolated situation, cause (someone or something) to be detached from surroundings" is from 1785. Electrical/chemical sense of "block from electricity or heat" (by interposition of a non-conductor) is from 1742. Related: Insulated; insulating.
insulation (n.): noun of action from insulate (v.) in its various senses. From 1767 as "a blocking from electricity or heat" (by interposition of a non-conductor). Sense of "state or action of being detached from others" is from 1798. Literal meaning "act of making (land) into an island" is from 1784; that of "state of being an island" is from 1799. The concrete sense of "insulating material" is recorded by 1870.
insulator (n.): 1801, agent noun in Latin form from insulate (v.). In reference to the glass or earthenware devices to hold telegraph (later telephone) wires, from 1840s.
insulin (n.): 1922 (earlier insuline, 1914), coined in English from Latin insula "island" (see isle and compare insula); so called because the hormone is secreted by the islets of Langerhans in the pancreas. Insuline was coined independently in French in 1909.
insult (v.): 1560s, "triumph over in an arrogant way" (obsolete), from Middle French insulter "to wrong; reproach; triumph arrogantly over," earlier "to leap upon" (14c.) and directly from Latin insultare "to assail, to make a sudden leap upon," which was used by the time of Cicero in sense of "to insult, scoff at, revile," frequentative of insilire "leap at or upon," from in- "on, at" (see in- (2)) + salire "to leap" (see salient (adj.)).

Sense of "verbally abuse, affront, assail with disrespect, offer an indignity to" is from 1610s. Related: Insulted; insulting.
insult (n.): c. 1600, "an attack;" 1670s as "an act of insulting, contemptuous treatment," from Middle French insult (14c.) or directly from Late Latin insultus "insult, scoffing," noun use of past participle of insilire, literally "to leap at or upon" (see insult (v.)). The older noun was insultation (1510s). To add insult to injury translates Latin injuriae contumeliam addere.
insulting (adj.): "containing or inflicting insult," 1590s, present-participle adjective from insult (v.). Related: insultingly.
insuperable (adj.): mid-14c., "unconquerable, incapable of being surmounted," from Old French insuperable (14c.) or directly from Latin insuperabilis "that cannot be passed over, unconquerable," from in- "not, opposite of" (see in- (1)) + superabilis "that may be overcome," from superare "to overcome," from superus "one that is above," from super "over" (see super-). Figurative use from 1650s. Related: Insuperably; insuperability.
insupportable (adj.): 1520s, from Middle French insupportable (14c.) or directly from Late Latin insupportabilis, from in- "not" (see in- (1)) + *supportabilis, from Latin supportare "to carry" (see support (v.)). Related: Insupportably.
insurable (adj.): 1786, from insure (v.) + -able. Related: Insurability.
insurance (n.): 1550s, "engagement to marry," a variant of ensurance "an assurance, pledge, guarantee," from Old French enseurance "assurance," from ensurer, from en- "make" (see en- (1)) + sur "safe, secure, undoubted" (see sure (adj.)).

Commercial sense of "security against loss or death in exchange for payment" is from 1650s. Assurance was the older word for this specific sense (late 16c.). Compare insure.
insure (v.): mid-15c., insuren, spelling variant of ensuren "to assure, give formal assurance" (late 14c.), also "make secure, make safe" (c. 1400), from Anglo-French enseurer, Old French ensurer, from en- "make" (see en- (1)) + seur, sur "safe, secure, undoubted" (see sure (adj.)).

The particular commercial senses of "make safe against loss by payment of premiums; undertake to ensure against loss, etc." are from mid-17c. (replacing assure in that meaning). Related: Insured; insuring.
insurer (n.): 1650s, agent noun from insure (v.).
insurgence (n.): 1776; see insurgent + -ence. Perhaps from French insurgence (by 1740s).
insurgency (n.): 1798, from insurgent + -cy.
insurgent (n.): "one who rises in revolt" against a government or its laws, 1745, from Latin insurgentem (nominative insurgens), present participle of insurgere "rise up, lift oneself; rise against; stand high, gather force," from in- "against," or here perhaps merely intensive, + surgere "to rise" (see surge (n.)).

An obsolete verb insurge (from French insurger) "to rise in opposition or insurrection" was common 16c. For verb forms 19c. writers sometimes turned to insurrectionize or insurrect.
insurmountable (adj.): 1690s, from in- (1) "not, opposite of" + surmountable. Related: Insurmountably. Brachet calls French insurmontable a "ghastly philological monster."
insurrection (n.): "an uprising against civil authority," early 15c., insurreccion, from Old French insurreccion or directly from Late Latin insurrectionem (nominative insurrectio) "a rising up," noun of action from past participle stem of insurgere "to rise up" (see insurgent).
insurrectionary (adj.): 1796, from insurrection + -ary. As a noun from 1893. Earlier adjectives were insurrectional (1794), insurrective (1590s), insurrectious (1630s). Insurrectionist (n.) is from 1811.
insusceptible (adj.): c. 1600; see in- (1) "not, opposite of" + susceptible (adj.). Perhaps modeled on French insusceptible (16c.).
intact (adj.): mid-15c., from Latin intactus "untouched, uninjured; undefiled, chaste; unsubdued," from in- "not" (see in- (1)) + tactus, past participle of tangere "to touch" (see tangent (adj.)).
intaglio (n.): "incised engraving" (as opposed to carving in relief), 1640s, from Italian intaglio "engraved work" (plural intagli), from intagliare "to cut in, engrave," from in- "in" (see in- (2)) + tagliare "to cut," from Late Latin taliare "to split" (see tailor (n.)).
intail (v.): obsolete form of entail. Related: Intailed; intailing.
intake (n.): c. 1800, "place where water is taken into a channel or pipe," from verbal phrase, from in (adv.) + take (v.). Meaning "act of taking in" (food, breath, etc.) is first attested 1808.