of unknown origin; attested in London criminal slang as adjective (1775, "counterfeit"), verb (1812, "to rob"), and noun (1851, "a swindle;" of persons 1888, "a swindler"), but probably older. A likely source is feague "to spruce up by artificial means," from German fegen "polish, sweep," also "to clear out, plunder" in colloquial use. "Much of our early thieves' slang is Ger. or Du., and dates from the Thirty Years' War" [Weekley]. Or it may be from Latin facere "to do." Century Dictionary notes that "thieves' slang is shifting and has no history."
The nautical word meaning "one of the windings of a cable or hawser in a coil" probably is unrelated, from Swedish veck "a fold." As a verb, "to feign, simulate" from 1941. To fake it is from 1915, jazz slang; to fake (someone) out is from 1940s, originally in sports. Related: Faked; fakes; faking.
The jazz musician's fake book is attested from 1951. Fake news "journalism that is deliberately misleading" is attested from 1894; popularized in the 2016 U.S. presidential campaign.
Old English col "not warm" (but usually not as severe as cold), "moderately cold, neither warm nor very cold," also, figuratively, of persons, "unperturbed, undemonstrative, not excited or heated by passions," from Proto-Germanic *koluz (source also of Middle Dutch coel, Dutch koel, Old High German chuoli, German kühl "cool," Old Norse kala "be cold"), from PIE root *gel- "cold; to freeze."
Attested in a figurative sense from early 14c. as "manifesting coldness, apathy, or dislike." Applied since 1728 to large sums of money to give emphasis to amount. Meaning "calmly audacious" is from 1825.
Slang use of cool for "fashionable" is by 1933, originally African-American vernacular; its modern use as a general term of approval is from the late 1940s, probably via bop talk and originally in reference to a style of jazz; the word is said to have been popularized in jazz circles by tenor saxophonist Lester Young (1909-1959). Cool-headed "not easily excited or confused" is from 1742.
"an act of licking," c. 1600, from lick (v.1). The earlier noun was licking (late 14c.; Old English had liccung). The meaning "small portion" is 1814, originally Scottish; hence the U.S. colloquial sense. Sense of "place where an animal goes to lick salt" is from 1747. The jazz music sense of "short figure or solo" is by 1922, perhaps from an earlier colloquial sense "a spurt or brisk run in racing" (1809). Meaning "a smart blow" (1670s) is from lick (v.2).
1550s, "act of melting by heat," from French fusion or directly from Latin fusionem (nominative fusio) "an outpouring, effusion," noun of action from fusus, past participle of fundere "to pour, melt" (from nasalized form of PIE root *gheu- "to pour"). Meaning "union or blending of different things; state of being united or blended" is by 1776; used especially in 19c, of politics, in early 20c. of psychology, atoms, and jazz (in nuclear physics sense, first recorded 1947; in musical sense, by 1972).