Online Etymology Dictionary

loosen (v.): late 14c., losnen, later lousen (early 15c.), from loose (v.) + -en (1). Related: Loosened; loosening.
low key (adj.): also low-key, 1895, from low (adj.) + key (n.1), perhaps from the musical sense.
distal (adj.): 1808, formed from distant + -al (1) on model of central, dorsal, ventral, etc.
patchwork (n.): "work composed of patches," 1690s, from patch (n.1) + work (n.). As an adjective from 1713.
dietician (n.): 1845, from diet (n.1) on model of physician. Earlier was dietist (c. 1600).
dietary (adj.): 1610s, from Medieval Latin dietarius, from Latin diaetarius, from diaeta (see diet (n.1)).
orbital (adj.): 1540s, with reference to eye sockets; 1839 with reference to heavenly bodies; from orbit (n.) + -al (1).
oratorical (adj.): 1580s, from orator or oratory + -ical, or else from Latin oratorius (see oratory (n.1)). Related: Oratorical; oratorically.
geographical (adj.): "pertaining to geography," 1550s, from Late Latin geographicus (from Greek geographikos, from geographia; see geography) + -al (1). Related: Geographically.
goofball (n.): "narcotic drug," 1938, slang, from goof + ball (n.1). As an intensive of goof (n.), it dates from 1959.
graven (adj.): "sculpted, carved," late 14c., past participle adjective from grave (v.) + -en (1).
keypad (n.): "handheld pad of labelled buttons to work electronics," 1975, from key (n.1) + pad (n.).
hatter (n.): late 14c., from hat + -er (1). Their association with madness dates to at least 1837.
headliner (n.): 1891, "one who writes newspaper headlines;" 1896 as "one who stars in a performance;" from headline + -er (1).
gunner (n.): mid-14c., gonner "one who works a cannon, catapult, or mangonel," from gun (n.) + -er (1).
hasten (v.): 1560s, transitive and intransitive, extended form of haste (v.) with -en (1). Related: Hastened; hastening.
helical (adj.): "spiral-shaped," c. 1600, from Latin helicem (nominative helix) "spiral" (see helix) + -al (1).
hosiery (n.): 1775, "stocking collectively, hose of all kinds," from hosier + -y (1). As "factory where hose is made," from 1803.
homicidal (adj.): 1725, from homicide + -al (1), or from Late Latin homicidalis. Related: Homicidally. As an adjective, homicidious is from 1630s.
homogamy (n.): 1805, "condition of bearing flowers that do not differ sexually," from homo- (1) "same" + -gamy.
hormonal (adj.): 1926, from hormone + -al (1). Earlier as a noun, the name of a spleen hormone. Related: Hormonally.
hud (n.): "husk of a seed," late 14c., of uncertain origin; perhaps related to or a dialectal form of hood (n.1).
inescapable (adj.): 1792, from in- (1) "not, opposite of" + escapable (see escape (v.)). Related: Inescapably.
pager (n.): "device that emits a signal when activated by a telephone call," 1968, agent noun from page (v.1).
irksome (adj.): "bothersome, troublesome, annoying," early 15c., from irk + -some (1). Related: Irksomely; irksomeness.
inoperable (adj.): "incapable of being treated by surgical operation," 1856, from in- (1) "not, opposite of" + operable.
insalubrious (adj.): 1630s, from Latin insalubris "unhealthy, unwholesome," or else a native formation from in- (1) "not, opposite of" + salubrious. Related: Insalubriety.
invariant (adj.): 1795, from in- (1) "not" + variant (adj.). As a noun, in mathematics, from 1851. Related: Invariance.
inviolate (adj.): "unbroken, intact," early 15c., from Latin inviolatus "unhurt," from in- "not, opposite of" (see in- (1)) + violatus (see violation).
irredeemable (adj.): c. 1600, from assimilated form of in- (1) "not, opposite of" + redeemable. Related: Irredeemably.
irreducible (adj.): 1530s, from assimilated form of in- (1) "not, opposite of" + reducible. Related: Irreducibly; irreducibility.
irretrievable (adj.): "not recoverable," 1690s (implied in irretrievably), from assimilated form of in- (1) "not, opposite of" + retrievable. Related: Irretrievability.
imprecise (adj.): 1804, from assimilated form of in- (1) "not, opposite of" + precise. Earlier was unprecise (1756). Related: Imprecisely.
improbable (adj.): 1590s, from assimilated form of in- (1) "not, opposite of" + probable, or else from Latin improbabilis. Related: Improbably.
incautious (adj.): 1650s, from in- (1) "not" + cautious (adj.). The Latin adjective was incautus. Related: Incautiously. Incaution (n.) is attested from 1715.
inaccurate (adj.): 1690s, from in- (1) "not" + accurate. Unaccurate is attested from 1670s. Related: Inaccurately (1660s).
inaction (n.): 1705, from in- (1) "not, opposite of" + action (n.). Perhaps modeled on French Inaction.
inactivity (n.): 1640s, from in- (1) "not, opposite of" + activity. Phrase masterly inactivity attested by 1791.
inadmissible (adj.): 1744, from in- (1) "not, opposite of" + admissible. Perhaps modeled on French inadmissible. Related: Inadmissibility.
inapposite (adj.): "not pertinent, not fit or suitable," 1620s (implied in inappositely), from in- (1) "not, opposite of" + apposite.
inapt (adj.): "ill-suited to the purpose or occasion," 1734, from in- (1) "not, opposite of" + apt. Related: Inaptly; inaptness. Compare inept.
inattention (n.): 1710, from in- (1) "not, opposite of" + attention. Perhaps modeled on French inattention.
indescript (adj.): "undescribed," 1831, from in- (1) "not, opposite of" + Latin descriptus, past participle of describere (see describe).
indecipherable (adj.): 1802, from in- (1) "not" + decipherable (see decipher (v.)). Undecipherable is older. Related: Indecipherably; indecipherability.
infelicitous (adj.): "unhappy, unlucky," 1754, from in- (1) "not, opposite of" + felicitous. Earlier was infelicious (1590s). Related: infelicitously; infelicitousness.
inexact (adj.): 1791, from in- (1) "not, opposite of" + exact (adj.). Perhaps modeled on French inexact (18c.). Related: Inexactly.
inefficacious (adj.): "not producing the desired effect," 1650s, from in- (1) "not, opposite of" + efficacious. Related: Inefficaciously; inefficaciousness (1640s).
intentional (adj.): 1520s, from intention + -al (1) or else from Medieval Latin intentionalis. Intentional fallacy recorded from 1946. Related: Intentionality.
internment (n.): 1840, "confinement within a place," from intern (v.1) + -ment. Compare French internement. Internment camp is attested from 1916.
interstitial (adj.): "pertaining to or situated in an interstice," 1640s, from Latin interstitium "interval" (see interstice) + -al (1). Related: Interstitially.