Online Etymology Dictionary

close quarters: 1753, originally nautical, and reflecting the confusion of close (v.) and close (adj.); "now understood of proximity, but orig. 'closed' space on ship-board where last stand could be made against boarders" [Weekley]. Cf. also closed-minded, a variant of close-minded attested from 1880s, with a sense of "shut" rather than "tight."
closed (adj.): past participle adjective from close (v.). Closed circuit is attested from 1827; closed shop in union sense from 1904; closed system first recorded 1896 in William James.
closet (n.): late 14c., from Old French closet "small enclosure, private room," diminutive of clos, from Latin clausum "closed space," from neuter past participle of claudere "to shut" (see close (v.)). In Matt. vi:6 it renders Latin cubiculum "bedchamber, bedroom," Greek tamieion "chamber, inner chamber, secret room;" thus originally in English "a private room for study or prayer." Modern sense of "small side-room for storage" is first recorded 1610s.

The adjective is from 1680s, "private, secluded;" meaning "secret, unknown" recorded from 1952, first of alcoholism, but by 1970s used principally of homosexuality; the phrase come out of the closet "admit something openly" first recorded 1963, and lent new meanings to the word out.
closure (n.): late 14c., "a barrier, a fence," from Old French closure "enclosure; that which encloses, fastening, hedge, wall, fence," also closture "barrier, division; enclosure, hedge, fence, wall" (12c., Modern French clôture), from Latin clausura "lock, fortress, a closing" (source of Italian chiusura), from past participle stem of claudere "to close" (see close (v.)). Sense of "act of closing, bringing to a close" is from early 15c. Sense of "tendency to create ordered and satisfying wholes" is 1924, from Gestalt psychology.
clot (n.): Old English clott, akin to Dutch kloot "ball," German Klotz "lump, block;" probably related to cleat and clod.
clot (v.): early 15c., from clot (n.). Of fluids from 1590s. Related: Clotted; clotting.
cloth (n.): Old English clað "a cloth, woven or felted material to wrap around one," hence, "garment," from Proto-Germanic *kalithaz (cf. Old Frisian klath, Middle Dutch cleet, Dutch kleed, Middle High German kleit, German Kleid "garment"), of obscure origin. The cloth "the clerical profession" is from 17c.
clothe (v.): Old English claþian, from clað (see cloth). Related: Clothed. Other Old English words for this were scrydan and gewædian.
clothes (n.): Old English claðas "cloths, clothes," originally plural of clað "cloth" (see cloth), which, in 19c., after the sense of "article of clothing" had faded from it, acquired a new plural form, cloths, to distinguish it from this word.
clothes horse (n.): also clothes-horse, "upright wooden frame for hanging clothes to dry," 1788, from clothes + horse. Figurative sense of "person whose sole function seems to be to show off clothes" is 1850.
clothesline (n.): 1830, from clothes + line (n.). As a kind of high tackle in U.S. football (the effect is similar to running into a taut clothesline) attested by 1970; as a verb by 1959.
clothespin (n.): also clothes-pin, by 1835, American English, from clothes + pin (n.).
clothier (n.): mid-15c. (late 13c. as a surname) Middle English agent noun from cloth; also see -ier.
clothing (n.): c.1200, verbal noun from clothe.
cloture (n.): 1871, the French word for "the action of closing," applied to debates in the French Assembly, then to the House of Commons and U.S. Congress, from French clôture, from Old French closture (see closure).
In foreign countries the Clôture has been used notoriously to barricade up a majority against the "pestilent" criticism of a minority, and in this country every "whip" and force is employed by the majority to re-assert its continued supremacy and to keep its ranks intact whenever attacked. How this one-sided struggle to maintain solidarity can be construed into "good for all" is inexplicable in the sense uttered. ["The clôture and the Recent Debate, a Letter to Sir J. Lubbock," London, 1882]
cloud (n.): Old English clud "mass of rock," related to clod. Metaphoric extension 13c. based on similarity of cumulus clouds and rock masses. The usual Old English word for "cloud" was weolcan. In Middle English, skie also originally meant "cloud." The four fundamental types of cloud classification (cirrus, cumulus, stratus, nimbus) were proposed by British amateur meteorologist Luke Howard (1772-1864) in 1802.
cloud (v.): early 15c., from cloud (n.). Related: Clouded; clouding.
Cloud Cuckoo Land: Imaginary city built in air, translating Aristophanes' Nephelokokkygia in "The Birds" (414 B.C.E.).
cloud nine (n.): by 1950, sometimes also cloud seven (1956, perhaps by confusion with seventh heaven), American English, of uncertain origin or significance. Some connect the phrase with the 1895 International Cloud-Atlas (Hildebrandsson, Riggenbach and Teisserenc de Bort), long the basic source for cloud shapes, in which, of the ten cloud types, cloud No. 9, cumulonimbus, was the biggest, puffiest, most comfortable-looking. Shipley suggests the sense in this and other expressions might be because, "As the largest one-figure integer, nine is sometimes used for emphasis." The phrase might appear in the 1935 aviation-based play "Ceiling Zero" by Frank Wilbur Wead.
cloudburst (n.): 1817, American English, from cloud (n.) + burst (n.). Parallels German Wolkenbruch.
cloudy (adj.): Old English cludig "rocky, full of cliffs;" see cloud (n.). Meaning "of the nature of clouds" is recorded from c.1300; meaning "full of clouds" is late 14c.; that of "not clear" is from 1580s. Figurative sense of "gloomy" is late 14c. Related: Cloudiness.
clough (n.): "ravine with a river," Old English cloh (in place names), of uncertain origin.
clout (n.): Old English clut "lump of something," also "patch of cloth put over a hole to mend it," from Proto-Germanic *klutaz (cf. Old Norse klute "kerchief," Danish klud "rag, tatter," Frisian klut "lump," Dutch kluit "clod, lump"); perhaps related to clot. In later use "a handkerchief," also "a woman's sanitary napkin." Sense of "a blow" is from early 14c., first in a verbal sense, "to beat, strike;" perhaps somehow from the "patch" sense. Sense of "personal influence" is 1958, on the notion of "punch, force."
clove (n.1): dried flowerbud of a tropical tree, used as a spice, late 15c., earlier clowes (14c.), from Anglo-French clowes de gilofre (c.1200), Old French clou de girofle "nail of gillyflower," so called from its shape, from Latin clavus "a nail" (see slot (n.2)). For second element, see gillyflower. The two cloves were much confused in Middle English.
clove (n.2): "slice of garlic," Old English clufu, from Proto-Germanic *klubo "cleft, thing cloven," from PIE *gleubh- "to tear apart, cleave" (see cleave (v.1)). Cognates mostly in compounds that translate as "clove-leek;" e.g. Old Saxon clufloc, Old High German chlobilouh. Dutch knoflook, German knoblauch are by dissimilation.
cloven (adj.): past participle adjective from cleave (v.1).
clover (n.): Old English clafre, from Proto-Germanic *klaibron (cf. Middle Low German klever, Middle Dutch claver, Dutch klaver, Old Saxon kle, Old High German kleo, German Klee "clover"), of uncertain origin.

Liberman suggests it is probably from West Germanic *klaiwaz- "sticky pap" (see clay), and adds, "The sticky juice of clover was the base of the most popular sort of honey." First reference in English to the suposed luck of a four-leaf clover is from c.1500. To be in clover "live luxuriously" is 1710, "clover being extremely delicious and fattening to cattle" [Johnson].
cloverleaf (n.): 1882, from clover + leaf (n.). Highway interchange sense attested by 1933.
Clovis: type of prehistoric stone spearpoints, 1943, from Clovis, New Mexico, U.S., near which place they were found. The town is said to have been named for the Frankish king Clovis (Latinized from Frankish Chlodovech, from Germanic masc. proper name *hluda-wigaz "famous in battle," cognate with Ludwig and Louis).
clowder: 1811, variant of clutter.
clown (n.): 1560s, also cloyne, "rustic, boor, peasant," origin uncertain. Perhaps from Scandinavian dialect (cf. Icelandic klunni "clumsy, boorish fellow;" Swedish kluns "a hard knob, a clumsy fellow"), or akin to North Frisian klönne "clumsy person," or, less likely, from Latin colonus "colonist, farmer." Meaning "fool, jester" is c.1600. "The pantomime clown represents a blend of the Shakes[pearean] rustic with one of the stock types of the It. comedy" [Weekley]. Meaning "contemptible person" is from 1920s.
clown (v.): c.1600, from clown (n.); colloquial sense of "to behave inappropriately" (e.g. clown around, 1932) attested by 1928, perhaps originally in music performance slang. Related: Clowned; clowning.
cloy (v.): "weary by too much, fill to loathing, surfeit," 1520s, from Middle English cloyen "hinder movement, encumber" (late 14c.), a shortening of accloyen (early 14c.), from Old French encloer "to fasten with a nail, grip, grasp," figuratively "to hinder, check, stop, curb," from Late Latin inclavare "drive a nail into a horse's foot when shoeing," from Latin clavus "a nail" (see slot (n.2)). The meaning "fill to a sateity, overfill" is attested for accloy from late 14c.
Accloye is a hurt that cometh of shooing, when a Smith driveth a nail in the quick, which make him to halt. [Edward Topsell, "The History of Four-footed Beasts," 1607]
Related: Cloyed; cloying.
cloze: 1953, in psychological writing, abstracted from closure.
club (n.): c.1200, "thick stick used as a weapon," from Old Norse klubba "cudgel," from Proto-Germanic *klumbon, related to clump (n.). Old English words for this were sagol, cycgel. Specific sense of "bat used in games" is from mid-15c. The social club (1660s) apparently evolved from this word 17c. from the verbal sense "gather in a club-like mass" (1620s), then "association of people" (1640s).
I got a good mind to join a club and beat you over the head with it. [Rufus T. Firefly]
Club sandwich first recorded 1903; club soda is 1877, originally a proprietary name. The club at cards (1560s) is the right name for the suit (Spanish basto, Italian bastone), but the pattern adopted on English cards is the French trefoil.
club (v.): "to hit with a club," 1590s, from club (v.). Meaning "gather in a club-like mass" is from 1620s. Related: Clubbed; clubbing.
CLUB, verb (military). -- In manoeuvring troops, so to blunder the word of command that the soldiers get into a position from which they cannot extricate themselves by ordinary tactics. [Farmer & Henley]
club-foot (n.): also clubfoot, 1530s, from club (n.) + foot (n.).
club-house (n.): also clubhouse, 1818, from club (n.) in the associative sense + house (n.). Clubhouse lawyer is baseball slang by 1940s.
cluck (v.): Old English cloccian originally echoic. Cf. Turkish culuk, one of the words for "turkey;" Greek klozan, Latin glocire, German glucken. Related: Clucked; clucking.
cluck (n.): 1703, from cluck (v.). Slang meaning "stupid person" (turkeys are famously foolish) is from 1927.
clue (n.): 1590s, phonetic variant of clew "a ball of thread or yarn," with reference to the one Theseus used as a guide out of the Labyrinth. The purely figurative sense of "that which points the way" is from 1620s.
clue (v.): "to inform someone of the important facts," usually with in, 1934, from clue (n.). Related: Clued; cluing. Earlier in 19c. sailing, "to man clue lines so as to force a yard down on the mast cap."
clueless (adj.): 1862, "trackless," from clue (n.) + -less. Meaning "ignorant, uninformed" is from 1943, said to be RAF slang from 1930s. Student slang use by 1985 is perhaps an independent extension along the same line. Related: Cluelessly; cluelessness.
clump (n.): 1580s, "lump, cluster of trees," from Middle English clompe "a lump" (c.1300), from Dutch klomp "lump, mass," or Middle Low German klumpe "clog, wooden shoe." Old English had clympre "lump, mass of metal."
clump (v.2): "walk heavily," 1660s, imitative. Related: Clumped; clumping.
clump (v.1): "to heap or gather in clumps" (transitive), 1824, from clump (n.). Related: Clumped; clumping. Intransitive sense "to form a clump or clumps" is recorded from 1896.
clumsy (adj.): 1590s, from Middle English clumsid "numb with cold" (14c.), past participle of clumsen "to benumb," from Old Norse klumsa, intensive of kluma "to make motionless." Related: Clumsily; clumsiness.
clung: Old English clungen, past tense and past participle of cling.
clunk (v.): 1796, "to make the sound of a cork being pulled from a bottle;" imitative. This was the main sense through most of 19c. Meaning "to hit, strike" is attested from 1940s. Related: Clunked; clunking.
clunker (n.): "anything inferior," 1940s, agent noun from clunk. Specific sense of "old car" was in use by 1951 (clunk in the sense "old worn-out machine" is from 1940s).