clingy (adj.) Look up clingy at Dictionary.com
1680s, of things, from cling + -y (2). Of persons (especially children) from 1969, though the image of a "clingy vine" in a relationship goes back to 1896. Related: Clinginess.
clinic (n.) Look up clinic at Dictionary.com
1620s, from French clinique (17c.), from Latin clinicus "physician that visits patients in their beds," from Greek klinike (techne) "(practice) at the sickbed," from klinikos "of the bed," from kline "bed, couch, that on which one lies," from suffixed form of PIE root *klei- "to lean."

Originally in English "bedridden person;" sense of "hospital" is 1884, from German Klinik in this sense, itself from French clinique, via the notion of "bedside medical education." The modern sense is thus reversed from the classical, when the "clinic" came to the patient. General sense of "conference for group instruction in something" is from 1919.
clinical (adj.) Look up clinical at Dictionary.com
1780, "pertaining to hospital patients or hospital care," from clinic + -al (2). Meaning "coldly dispassionate" (like a medical report) is recorded from 1928. Related: Clinically.
clinician (n.) Look up clinician at Dictionary.com
1844, from French clinicien, from Latin clinicus (see clinic).
clink (v.) Look up clink at Dictionary.com
early 14c., echoic (compare Dutch klinken, Old High German klingan, German klingen). Related: Clinked; clinking. The noun in the sound sense is from c. 1400.
clink (n.2) Look up clink at Dictionary.com
"prison," 1770s, apparently originally (early 16c.) the Clynke on Clink Street in Southwark, on the estate of the bishops of Winchester. To kiss the clink "to be imprisoned" is from 1580s, and the word and the prison name might be cognate derivatives of the sound made by chains or metal locks (see clink (v.)).
clink (n.1) Look up clink at Dictionary.com
"sharp, ringing sound made by collision of sonorous (especially metallic) bodies," c. 1400, from clink (v.).
clinker (n.) Look up clinker at Dictionary.com
"mass of slag," 1769, from klincard (1640s), a type of paving brick made in Holland, from Dutch klinkaerd, from klinken "to ring" (as it does when struck), of imitative origin. Also "a clinch-nail;" hence clinker-built (1769). The meaning "stupid mistake" is first recorded 1950 in American English; originally (1942) "a wrong note in music."
clino- Look up clino- at Dictionary.com
before vowels clin-, word-forming element meaning "slope, slant, incline," from Latinized form of Greek klinein "to lean, slope," from PIE root *klei- "to lean."
clinometer (n.) Look up clinometer at Dictionary.com
"measurer of slopes and elevations," 1811, from clino- + -meter. Related: Clinometric.
Clio Look up Clio at Dictionary.com
"muse of history, muse who sings of glorious actions," usually represented with a scroll and manuscript case, from Latin Clio, from Greek Kleio, literally "the proclaimer," from kleiein "to tell of, celebrate, make famous," from kleos "rumor, report, news; good report, fame, glory," from PIE *klew-yo-, suffixed form of root *kleu- "to hear."
clip (n.1) Look up clip at Dictionary.com
"something for attaching or holding," mid-14c., probably from clip (v.2). Meaning "receptacle containing several cartridges for a repeating firearm" is from 1901. Meaning "piece of jewelry fastened by a clip" is from 1937. This is also the source of paper clip (1854). Old English had clypp "an embrace."
clip (n.2) Look up clip at Dictionary.com
mid-15c., "shears," from clip (v.1). Meaning "act of clipping" is from 1825, originally of sheep-shearing, later of haircuts. Meaning "rate of speed" is 1867 (compare clipper). Meaning "an extract from a movie" is from 1958.
clip (v.1) Look up clip at Dictionary.com
"to cut or sever with a sharp instrument," c. 1200, from a Scandinavian source (compare Old Norse klippa, Swedish klippa, Danish klippe "clip, shear, cut"), which is probably echoic. Related: Clipped; clipping.

Meaning "to pronounce short" is from 1520s. The verb has a long association with shady activities, originally especially in reference to cutting or shaving metal from coins (c. 1400), but later extended to swindles from the sense "to shear sheep," hence clip-joint "place that overcharges outrageously" (1933, American English, a term from Prohibition). To clip (someone's) wings figuratively (1590s) is from the method of preventing a captive bird from flying.
clip (v.2) Look up clip at Dictionary.com
"fasten, hold together by pressure," also (mostly archaic) "to embrace," from Old English clyppan "to embrace, clasp; surround; prize, honor, cherish;" related to Old Frisian kleppa "to embrace, love," Old High German klaftra, German klafter "fathom" (on notion of outstretched arms). Also compare Lithuanian glebys "armful," glomti "to embrace." Meaning "to fasten, bind" is early 14c. Meaning "to fasten with clips" is from 1902. Related: Clipped; clipping. Original sense of the verb is preserved in U.S. football clipping penalty.
clip-clop Look up clip-clop at Dictionary.com
sound as of a horse's hooves, 1884, imitative.
clip-on (adj.) Look up clip-on at Dictionary.com
1909, from clip (v.2) + on.
clipboard (n.) Look up clipboard at Dictionary.com
1904, from clip (n.1) + board (n.1). Portable board with a hinged clip at the top to hold papers.
clipper (n.) Look up clipper at Dictionary.com
late 14c., "sheepshearer;" early 15c., "a barber;" c. 1300 as a surname; agent noun from Middle English clippen "shorten" (see clip (v.1)). The type of fast sailing ship so called from 1823 (in Cooper's "The Pilot"), probably from clip (v.1) in sense of "to move or run rapidly," hence early 19c. sense "person or animal who looks capable of fast running." Perhaps originally simply "fast ship," regardless of type:
Well, you know, the Go-along-Gee was one o' your flash Irish cruisers -- the first o' your fir-built frigates -- and a clipper she was! Give her a foot o' the sheet, and she'd go like a witch--but somehow o'nother, she'd bag on a bowline to leeward. ["Naval Sketch-Book," by "An officer of rank," London, 1826]
The early association of the ships was with Baltimore, Maryland. Perhaps influenced by Middle Dutch klepper "swift horse," echoic (Clipper appears as the name of an English race horse in 1831). In late 18c., the word principally meant "one who cuts off the edges of coins" for the precious metal.
clippers (n.) Look up clippers at Dictionary.com
"shears-like cutting tool for hair, etc.," 1876, agent noun from clip (v.1). Earlier they were clipping shears (mid-15c.).
clipping (n.1) Look up clipping at Dictionary.com
early 13c., "clasping, embracing," verbal noun from clip (v.2). As a U.S. football penalty (not in OED), from 1920.
Clipping or Cutting Down from Behind. -- This is to be ruled under unnecessary roughness, and penalized when it is practiced upon "a man obviously out of the play." This "clipping" is a tendency in the game that the committee is watching anxiously and with some fear. ["Colliers," April 10, 1920]
clipping (n.2) Look up clipping at Dictionary.com
"a cutting," early 14c., verbal noun from clip (v.1). Sense of "a small piece cut off" is from late 15c. Meaning "an article cut from a newspaper" is from 1857.
clique (n.) Look up clique at Dictionary.com
1711, "a party of persons; a small set, especially one associating for exclusivity," from obsolete French clique, originally (14c.) "a sharp noise," also "latch, bolt of a door," from Old French cliquer "click, clatter, crackle, clink," 13c., echoic. Apparently this word was at one time treated in French as the equivalent of claque (q.v.) and partook of that word's theatrical sense.
cliquish (adj.) Look up cliquish at Dictionary.com
1839, from clique + -ish. Related: Cliquishly; cliquishness.
clit (n.) Look up clit at Dictionary.com
by 1969, slang shortening of clitoris.
clitellum (n.) Look up clitellum at Dictionary.com
"raised band around an earthworm," 1816, Modern Latin, from Latin clitellae "a pack-saddle," diminutive of *clitra "litter," from PIE *kleitro-, suffixed form of root *klei- "to lean." Related: Clitellar.
clitoral (adj.) Look up clitoral at Dictionary.com
1887, from stem of clitoris + -al (1). Related: Clitorally. Alternative form clitorial is attested from 1879.
clitoridectomy (n.) Look up clitoridectomy at Dictionary.com
1866, from Greek klitorid- (see clitoris) + -ectomy. Originally in reference to a proposed cure for hysteria.
clitoris (n.) Look up clitoris at Dictionary.com
"erectile organ of female mammals," 1610s, coined in Modern Latin from Late Greek kleitoris, a diminutive, but the exact sense intended by the coiners is uncertain. Perhaps from Greek kleiein "to sheathe," also "to shut," in reference to its being covered by the labia minora. The related Greek noun form kleis has a second meaning of "a key, a latch or hook (to close a door);" see close (v.), and compare slot (n.2).

Alternatively [Watkins], from Greek kleitys, a variant of klitys "side of a hill," from PIE *kleitor-, suffixed form of root *klei- "to lean," via with a sense of "little hill." Some ancient medical sources give a supposed Greek verb kleitoriazein "to touch or titillate lasciviously, to tickle" (compare German slang der Kitzler "clitoris," literally "the tickler"), but the verb is likely from the anatomy in this case.

The anatomist Mateo Renaldo Colombo (1516-1559), professor at Padua, claimed to have discovered it ("De re anatomica," 1559, p. 243). He called it amor Veneris, vel dulcedo "the love or sweetness of Venus." It had been known earlier to women.
cloaca (n.) Look up cloaca at Dictionary.com
1650s, euphemism for "underground sewer," from Latin cloaca "public sewer, drain," from cluere "to cleanse," from PIE root *kleue- "to wash, clean" (source also of Greek klyzein "to dash over, wash off, rinse out," klysma "liquid used in a washing;" Lithuanian šluoju "to sweep;" Old English hlutor, Gothic hlutrs, Old High German hlutar, German lauter "pure, clear"). Use in biology, in reference to eliminatory systems of lower animals, is from 1834. Related: Cloacal (1650s); cloacinal (1857).
cloak (v.) Look up cloak at Dictionary.com
c. 1500, from cloak (n.). Figuratively from 1540s. Related: Cloaked; cloaking.
cloak (n.) Look up cloak at Dictionary.com
late 13c., "long, loose outer garment," from Old North French cloque (Old French cloche, cloke) "traveling cloak," from Medieval Latin clocca "travelers' cape," literally "a bell," so called from the garment's bell-like shape (the word is thus a doublet of clock (n.1)). An article of everyday wear in England through 16c., somewhat revived 19c. as a fashion garment. Cloak-and-dagger (adj.) attested from 1848, said to be ultimately translating French de cape et d'épée, suggestive of stealthy violence and intrigue.
Other "cloak and dagger pieces," as Bouterwek tells us the Spaniards call their intriguing comedies, might be tried advantageously in the night, .... ["Levana; or the Doctrine of Education," English translation, London, 1848]
cloak-room (n.) Look up cloak-room at Dictionary.com
also cloakroom, 1852, from cloak (n.) + room (n.).
clobber (v.) Look up clobber at Dictionary.com
1941, British air force slang, probably related to bombing; possibly echoic. Related: Clobbered; clobbering. In late 19c. British slang the word principally had to do with clothing, as in clobber (n.) "clothes," (v.) "to dress smartly;" clobber up "to patch old clothes for reuse."
cloche (n.) Look up cloche at Dictionary.com
type of bell-jar, 1882, from French cloche "bell, bell glass" (12c.), from Late Latin clocca "bell" (see clock (n.1)). As a type of women's hat, recorded from 1907, so called from its shape.
clock (v.) Look up clock at Dictionary.com
"to time by the clock," 1883, from clock (n.1). The slang sense of "hit, sock" is 1941, originally Australian, probably from earlier slang clock (n.) "face" (1923). Related: Clocked; clocking.
clock (n.1) Look up clock at Dictionary.com
late 14c., clokke, originally "clock with bells," probably from Middle Dutch clocke (Dutch klok) "a clock," from Old North French cloque (Old French cloke, Modern French cloche "a bell"), from Medieval Latin (7c.) clocca "bell," which is probably from Celtic (compare Old Irish clocc, Welsh cloch, Manx clagg "a bell") and spread by Irish missionaries (unless the Celtic words are from Latin); ultimately of imitative origin.

Replaced Old English dægmæl, from dæg "day" + mæl "measure, mark" (see meal (n.1)). The Latin word was horologium; the Greeks used a water-clock (klepsydra, literally "water thief"). Image of put (or set) the clock back "return to an earlier state or system" is from 1862. Round-the-clock (adj.) is from 1943, originally in reference to air raids. To have a face that would stop a clock "be very ugly" is from 1886. (Variations from c. 1890 include break a mirror, kill chickens.)
I remember I remember
That boarding house forlorn,
The little window where the smell
Of hash came in the morn.
I mind the broken looking-glass,
The mattress like a rock,
The servant-girl from County Clare,
Whose face would stop a clock.

[... etc.; "The Insurance Journal," Jan. 1886]
clock (n.2) Look up clock at Dictionary.com
"ornament pattern on a stocking," 1520s, probably identical with clock (n.1) in its older sense and meaning "bell-shaped ornament."
clock-radio (n.) Look up clock-radio at Dictionary.com
1946, from clock (n.1) + radio (n.).
clock-watcher (n.) Look up clock-watcher at Dictionary.com
"employee habitually prompt in leaving," 1887, from clock (n.1) + agent noun from watch (v.). Related: Clock-watching. Compare earlier tell-clock "idler" (c. 1600).
clockwise (adv.) Look up clockwise at Dictionary.com
also clock-wise, "in the direction of the hands of a clock," 1879, from clock (n.1) + wise (n.).
clockwork (n.) Look up clockwork at Dictionary.com
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).
clod (n.) Look up clod at Dictionary.com
"lump of earth or clay," Old English clod- (in clodhamer "the fieldfare," a kind of thrush, literally "field-goer"), from Proto-Germanic *kludda-, from PIE *gleu- (see clay).

Synonymous with collateral clot until meaning differentiated 18c. Meaning "person" ("mere lump of earth") is from 1590s; that of "blockhead" is from c. 1600 (compare clodpate, clodpoll, etc.). It also was a verb in Middle English, meaning both "to coagulate, form into clods" and "to break up clods after plowing."
cloddish (adj.) Look up cloddish at Dictionary.com
1844, from clod (n.) + -ish. Related: Clodishly; clodishness.
clodhopper (n.) Look up clodhopper at Dictionary.com
1690s, slang, "one who works on plowed land, a rustic," from clod (n.) + agent noun from hop (v.). Compare in a similar sense clod-breaker, clod-crusher; in this word perhaps a play on grasshopper. Sense extended by 1836 to the shoes worn by such workers.
clog (v.) Look up clog at Dictionary.com
late 14c., "hinder," originally by fastening a block of wood to something, from clog (n.). Meaning "choke up with extraneous matter" is 17c. Related: Clogged; clogging.
clog (n.) Look up clog at Dictionary.com
early 14c., clogge "a lump of wood," origin unknown. Also used in Middle English of large pieces of jewelry and large testicles. Compare Norwegian klugu "knotty log of wood." Meaning "anything that impedes action" is from 1520s. The sense of "wooden-soled shoe" is first recorded late 14c.; they were used as overshoes until the introduction of rubbers c. 1840. Originally all wood (hence the name), later wooden soles with leather uppers for the front of the foot only. Later revived in fashion (c. 1970), primarily for women. Clog-dancing is attested from 1863.
cloison (n.) Look up cloison at Dictionary.com
"a partition, a dividing band," 1690s, from French cloison, from Vulgar Latin *clausionem (nominative *clausio), noun of action from past participle stem of Latin claudere "to close, shut" (see clause). Related: Cloisonnage.
cloisonne (adj.) Look up cloisonne at Dictionary.com
"divided into compartments," 1863, from French cloisonné, from cloison "a partition" (12c., in Old French, "enclosure"), from Provençal clausio, from Vulgar Latin *clausio, noun of action from past participle stem of claudere "to close, shut" (see clause).
cloister (v.) Look up cloister at Dictionary.com
c. 1400 (implied in cloistered), from cloister (n.). Figurative use from c. 1600. Related: Cloistered; cloistering.