madcap

late 13c., "disordered in intellect, demented, crazy, insane," from Old English gemædde "out of one's mind" (usually implying also violent excitement), also "foolish, extremely stupid," earlier gemæded "rendered insane," past participle of a lost verb *gemædan "to make insane or foolish," from Proto-Germanic *gamaidjan, demonstrative form of *gamaidaz "changed (for the worse), abnormal" (source also of Old Saxon gimed "foolish," Old High German gimeit "foolish, vain, boastful," Gothic gamaiþs "crippled, wounded," Old Norse meiða "to hurt, maim").

This apparently is from the Germanic intensive prefix *ga- + PIE *moito-, past participle of root *mei- (1) "to change, go, move" (source also of Latin mutare "to change," migrare "to change one's place of residence"). In Middle English usurped the place of the more usual Old English word, wod (see wood (adj.)).

The meanings "beside oneself with excitement or enthusiasm, under the influence of uncontrollable emotion" and "enraged, furious, beside oneself with anger" are attested from early 14c., but the latter was deplored by Rev. John Witherspoon (1781) as an Americanism. It now competes in American English with angry for this sense. Of animals, "affected with rabies, furious from disease" from late 13c.

To do something like mad "recklessly, as if mad or crazy" is by 1650s. Phrase mad as a March hare is attested from 1520s, via notion of breeding season; mad as a hatter is from 1829 as "demented," 1837 as "enraged," according to a modern theory supposedly from erratic behavior caused by prolonged exposure to poison mercuric nitrate, used in making felt hats. For mad as a wet hen see hen.

Mad money, which a young woman carries for use in getting home when she and her date have a falling out, is attested by 1922; mad scientist, one so eccentric as to be dangerous or evil, is by 1891. Mad Libs, the word game (based on the idea in consequences, etc.), was first published in 1958

late Old English cæppe "hood, head-covering, cape," a general Germanic borrowing (compare Old Frisian and Middle Dutch kappe, Old High German chappa) from Late Latin cappa "a cape, hooded cloak" (source of Spanish capa, Old North French cape, French chape), a word of uncertain origin. Possibly a shortened from capitulare "headdress," from Latin caput "head" (from PIE root *kaput- "head").

The Late Latin word apparently originally meant "a woman's head-covering," but the sense was transferred to "hood of a cloak," then to "cloak" itself, though the various senses co-existed. Old English took in two forms of the Late Latin word, one meaning "head-covering," the other "ecclesiastical dress" (see cape (n.1)). In most Romance languages, a diminutive of Late Latin cappa has become the usual word for "head-covering" (such as French chapeau).

The meaning "soft, small, close-fitted head covering" in English is from early 13c., originally for women; extended to men late 14c.; extended to cap-like coverings on the ends of anything (as in hubcap) from mid-15c. The meaning "contraceptive device" is by 1916.

The meaning "cap-shaped piece of copper lined with gunpowder and used to ignite a firearm" is by 1825, hence cap-gun (1855); extended to paper strips used in toy pistols by 1872 (cap-pistol is from 1879).

Figurative thinking cap is from 1839 (considering cap is 1650s). Cap and bells (1781) was the insignia of a fool; cap and gown (1732) of a scholar. To set one's cap at or for (1773) means "use measures to gain the regard or affection of," usually in reference to a woman seeking a man's courtship.