Online Etymology Dictionary

moisten (v.): 1570s, from moist + -en (1). Related: Moistened; moistening. The earlier verb was simply moist (early 14c.), from Old French moistir.
empyreal (adj.): late 15c., "pertaining to the highest heaven," from Medieval Latin empyreus (see empyrean) + -al (1). Confused by early writers with imperial.
checkout (n.): 1944, from check (v.1) + out (adv.). Originally "training given to a pilot for using a specific aircraft;" hotel sense is from 1958.
chiral (adj.): 1894, a hybrid coined by Lord Kelvin from Latinized comb. form of Greek kheir "hand" (from PIE *ghes- "hand;" see chiro-) + -al (1).
consensual (adj.): 1754, "having to do with consent," from stem of Latin consensus (see consensus) + -al (1). Meaning "by consent" is attested from 1800.
consequential (adj.): 1620s, from consequent (Latin consequentia) + -al (1). Meaning "pregnant with consequences, important" is recorded from 1728. Related: Consequentially (c. 1600).
clockwork (n.): also clock-work, 1660s, "mechanism of a clock," from clock (n.1) + work (n.). Figurative sense of "anything of unvarying regularity" is recorded earlier (1620s).
cockerel (n.): "young cock," mid-15c. (late 12c. as a surname), apparently a diminutive of cock (n.1). Despite the form, no evidence that it is from French.
banquette (n.): 1620s, "raised platform in a fortification," from French banquette (15c.), from Italian banchetta, diminutive of banca "bench, shelf" (see bank (n.1)).
backdate (v.): also back-date, by 1881 (implied in back-dated), from back (adv.) + date (v.1). Compare antedate. Related: Backdated; backdating.
volleyball (n.): 1896, from volley (n.) in the sporting sense + ball (n.1). So called because the ball must be returned before it hits the ground.
masthead (n.): 1748, "top of a ship's mast" (the place for the display of flags), hence, from 1838, "top of a newspaper;" from mast (n.1) + head (n.).
lightening (n.): "the shedding of light," mid-14c., verbal noun from lighten (v.2). Meaning "alleviation of weight" (literal and figurative) is from 1520s, from lighten (v.1).
mockingbird (n.): also mocking-bird, 1670s, from mocking (adj.), 1520s, from present participle of mock (v.) + bird (n.1). Earlier form was mock-bird (1640s).
discovery (n.): 1550s, "fact of discovering;" see discover + -y (1). Earlier in this sense was discovering (mid-14c.). Meaning "that which is discovered" is from 1630s.
palatinate (n.): 1650s, from palatine + -ate (1). In England and Ireland, a county palatine; also used of certain American colonies (Carolina, Maryland, Maine).
otherworldly (adj.): 1854, from other + world + -ly (1). Otherworldliness is recorded from 1819. Phrase other world "world of idealism or fantasy, afterlife, spirit-land" is c. 1200.
otalgia (n.): 1650s, from Greek otalgia "earache," from ous, aus (genitive otos) "ear" (see ear (n.1)) + algos "pain" (see -algia).
genealogical (adj.): 1570s, from French généalogique, from généalogie (see genealogy) + -al (1). Earlier in the same sense was genealogial (mid-15c.). Related: Genealogically.
geographer (n.): "one versed in geography," 1540s, from geography + agent noun ending -er (1). The Greek word was geographos (Medieval Latin geographus).
gimpy: 1925 as a noun, "lame person;" 1931 as an adjective, "lame, crippled," hobo slang, from gimp (n.1) + -y (3) and (2).
keystroke (n.): 1902, from key (n.1) + stroke (n.). Not in common use until the rise of computers. As a verb, by 1966 (implied in keystroking).
hot water (n.): c. 1400, literal; 1530s in figurative sense of "trouble." See hot (adj.) + water (n.1). Hot-water bottle is from 1895.
raillery (n.): "good-humored ridicule," 1650s, from rail (v.) + -ery, or perhaps from French raillerie, from Middle French railler "to tease" (see rail (v.1)).
insincerity (n.): 1540s, from in- (1) "not, opposite of" + sincerity, or else from Latin insincerus "not genuine, not pure; spoiled, corrupted" (see insincere).
instate (v.): also enstate, "to put someone in a certain state or condition," c. 1600, from in + state (n.1). Related: Instated; instating.
irreproachable (adj.): 1630s, from French irréprochable (15c.), from assimilated form of in- "not, opposite of" (see in- (1)) + réprochable (see reproach (n.)). Related: Irreproachably.
impractical (adj.): 1823, from assimilated form of in- (1) "not, opposite of" + practical (adj.). Impracticable in the same sense dates from 1670s; unpractical is rare. Related: Impractically.
inalienable (adj.): "that cannot be given up," 1640s, from in- (1) "not, opposite of" + alienable (adj.). Perhaps from French inaliénable (16c.). Related: Inalienably; Inalienability.
indefeasible (adj.): "not to be set aside or overcome," 1530s (implied in indefeasibly), from in- (1) "not, opposite of" + defeasible (see defeasance).
inexplicit (adj.): 1775 (implied in inexplicitly), from in- (1) "not, opposite of" + explicit. Or else from Latin inexplicitus "not to be unfolded; unexplained." Related: Inexplicitly; inexplicitness.
infertile (adj.): 1590s, from French infertile (15c.), from Late Latin infertilis "unfruitful," from in- "not, opposite of" (see in- (1)) + Latin fertilis "fruitful, productive" (see fertile).
inelastic (adj.): 1748, "not rebounding after a strain," from in- (1) "not, opposite of" + elastic (adj.). Figurative sense "rigid, unyielding" attested by 1867. Related: Inelasticity.
inexhaustible (adj.): c. 1600, from in- (1) "not, opposite of" + exhaustible (see exhaust (v.)). Perhaps modeled on French inexhaustible (15c.). Related: Inexhaustibly.
sawhorse (n.): "support or rack for holding wood while it is cut by a saw," 1778, from saw (n.1) + horse (n.) in the mechanical sense.
sickly (adj.): late 14c., "ill, invalid, habitually ailing," from sick (adj.) + -ly (1). Meaning "causing sickness" in any sense is from c. 1600. Related: Sickliness.
scalable (adj.): 1570s, "able to be climbed;" see scale (v.1) + -able. From 1936 as "able to be graded by scale." Related: Scalably; scalability.
shiftless (adj.): "wanting in resources or energy and ability to shift for oneself," 1580s, from shift (n.1) in the sense "resources" + -less. Related: Shiftlessly; shiftlessness.
sideboard (n.): "table placed near the side of a room or hall" (especially one where food is served), c. 1300, from side (adj.) + board (n.1).
soleus (n.): muscle of the calf of the leg, 1670s, Modern Latin, from Latin solea "sole" (see sole (n.1)). So called for its flatness.
spearmint (n.): 1530s, from spear (n.2) + mint (n.1). "Said to be a corruption of spire-mint, with reference to the pyramidal inflorescence" [Century Dictionary].
-scope: word-forming element indicating "an instrument for seeing," from Late Latin -scopium, from Greek -skopion, from skopein "to look at, examine" (see scope (n.1)).
impassable (adj.): "that cannot be passed or passed over," 1560s, from assimilated form of in- (1) "not, opposite of" + passable. Related: Impassability.
imperishable (adj.): "not subject to destruction or decay," 1640s, from assimilated form of in- "not, opposite of" (see in- (1)) + perishable. Related: Imperishably
impenitent (adj.): early 15c., from Latin impaenitentem, from assimilated form of in- "not, opposite of" (see in- (1)) + paenitens (see penitence). As a noun, "hardened sinner," from 1530s.
incommodious (adj.): 1550s, from in- (1) "not, opposite of" + commodious. Related: Incommodiously. A verb, incommode, is attested from late 16c., from Latin incommodare. The Latin adjective was incommodus "inconvenient."
inconsolable (adj.): 1590s, from Latin inconsolabilis "inconsolable," from in- "not" (see in- (1)) + consolabilis "consolable," from consolari (see console (v.)). Related: Inconsolably (c. 1500).
incontestable (adj.): 1670s, from in- "not" (see in- (1)) + contestable (see contest (v.)). Perhaps from or modeled on French incontestable. Related: Incontestably.
incongruent (adj.): mid-15c., from Late Latin incongruentem (nominative incongruens), from in- "not" (see in- (1)) + congruens (see congruent). Related: Incongruently.
poacher (n.): 1660s, "one who poaches game," agent noun from poach (v.1). Attested from 1846 as "vessel for poaching eggs," from poach (v.2).