Online Etymology Dictionary

foolproof: 1902, Amer.Eng., "safe against the incompetence of a fool," from fool (n.) + proof (q.v.).
fool (n.): c.1275, from O.Fr. fol "madman, insane person," also an adj. meaning "mad, insane," from L. follis "bellows, leather bag," in V.L. used with a sense of "windbag, empty-headed person" (see follicle). Cf. also Skt. vatula- "insane," lit. "windy, inflated with wind."
"The word has in mod.Eng. a much stronger sense than it had at an earlier period; it has now an implication of insulting contempt which does not in the same degree belong to any of its synonyms, or to the derivative foolish." [OED]
Meaning "jester, court clown" first attested 1370, though it is not always possible to tell whether the reference is to a professional entertainer or an amusing lunatic on the payroll. As the name of a kind of custard dish, it is attested from 1598 (the food was also called trifle, which may be the source of the name). The verb meaning "to make a fool of" is recorded from 1596. Feast of Fools (c.1320), from M.L. festum stultorum) refers to the burlesque festival celebrated in some churches on New Year's Day in medieval times. Fool's gold "iron pyrite" is from 1882. Fool's paradise "state of illusory happiness" is from 1462. Fool around is 1875 in the sense of "pass time idly," 1970s in sense of "have sexual adventures." Foolosopher, a most useful insult, turns up in a 1549 translation of Erasmus.
foolhardy: early 13c., from fool (n.) + M.E. hardi "bold;" hence "foolishly brave."
muggins: "fool, simpleton," 1855, apparently from the surname, perhaps influenced by slang mug "dupe, fool" (see mug (n.2)).
vamp (n.): "seductive woman," 1911, short for vampire. First attested use is earlier than the release of the Fox film "A Fool There Was" (January 1915), with sultry Theda Bara in the role of The Vampire. But the movie was based on a play of that name that had been a Broadway hit (title and concept from a Kipling poem, "The Vampire"), and the word may ultimately trace to Bara's role. At any rate, Bara (real name Theodosia Goodman) remains the classic vamp.
A fool there was and he made his prayer
(Even as you and I!)
To a rag and a bone and a hank of hair
(We called her the woman who did not care)
But the fool, he called her his lady fair
(Even as you and I.)

[Kipling, "The Vampire"]
Seven Sisters: "the Pleiades," 1412 (see Pleiades), seven daughters of Atlas and Pleione, placed among the stars by Zeus. As a name for the major multi-national petroleum companies, it is attested from 1962. They were listed in 1976 as Exxon, Mobil, Gulf, Standard Oil of California, Texaco, British Petroleum, and Royal Dutch Shell. The Pleiades also are known as the Seven Stars (O.E. sibunsterri), though in 15c. this name occasionally was given to the Big Dipper.
FOOL: ... The reason why the
seven stars are no more than seven is a pretty reason.
KING LEAR: Because they are not eight?
FOOL: Yes, indeed: thou wouldst make a good fool.
["King Lear," Act I, Scene V]
patch (2): "fool, clown," 1549, perhaps from It. pazzo "fool," which is possibly from O.H.G. barzjan "to rave." Form perhaps infl. by folk-etymology from patch (1), on notion of a fool's patched garb.
cockscomb: c.1400, "comb or crest of a cock," from possessive of cock + comb. Meaning "cap worn by a professional fool" is from 1560s; hence "conceited fool" (1560s), a sense passing into the derivative coxcomb.
berk: "fool," 1936, abbreviation of Berkshire Hunt, rhyming slang for cunt but typically applied only to contemptible persons, not to the body part.
"This is not an objective, anatomical term, neither does it imply coitus. It connects with that extension of meaning of the unprintable, a fool, or a person whom one does not like." ["Dictionary of Rhyming Slang," 1960]
elude: 1530s, "delude, make a fool of," from L. eludere "escape from, make a fool of, win from at play," from ex- "out, away" + ludere "to play" (see ludicrous). Sense of "evade" is first recorded 1610s.
fond: c.1340, originally "foolish, silly," from pt. of fonnen "to fool, be foolish," perhaps from M.E. fonne "fool," of uncertain origin, or related to fun. Meaning evolved by 1590 via "foolishly tender" to "having strong affections for." Another sense of fonne was "to lose savor," which may be the original meaning of the word (e.g. Wyclif: "Gif þe salt be fonnyd it is not worþi," 1380).
April fool: 1680s; April-gowk (from O.N. gaukr "a cuckoo") is a northern variant. April Fool's Day customs of sending people on false errands seem to have come to Eng. from France late 17c.; originally All Fool's Day (1712). In Cumberland, Westmorland and northern parts of Lancashire and Yorkshire, however, May 1 was the day for hoaxing, and the fool was a May gosling. That custom was first attested 1791.
waggish: "willing to make a fool of oneself, and fond of doing so to others," 1589, see wag (n.).
smash (n.): 1839, "failure, financial collapse," from smash (v.). Tennis sense is from 1882. Meaning "great success" is from 1923 ("Variety" headline, Oct. 16, in ref. to Broadway productions of "The Fool" and "The Rise of Rosie O'Reilly").
bob (1): "short, jerking motion," late 14c., probably connected to M.E. bobben "to strike, beat" (late 13c.), perhaps of echoic origin. Another early sense was "to make a fool of, cheat" (early 14c.). As a slang word for "shilling" it is attested from 1789, but the signification is unknown.
motley: late 14c., from Anglo-Fr. motteley, probably from O.E. mot "speck" (see mote). "Diversified in color," especially of a fool's dress. Hence, allusively, "a fool" (1600).
fop: 1440, "foolish person," perhaps related to fob (v.) via Ger. foppen "jeer at, make a fool of" (see fob (v.)). Sense of "dandy" is 1670.
bamboozle: 1703, originally a slang or cant word, perhaps Scottish from bombaze "perplex," related to bombast, or Fr. embabuiner "to make a fool (lit. 'baboon') of."
pratfall: 1939, from prat "buttocks" (1567), originally criminals' slang, of unknown origin. Prat in British slang sense of "dolt, fool" is recorded from 1968.
dodo: 1628, from Port. doudo "fool, simpleton," an insult applied by Port. sailors to the awkward bird (Didus ineptus) they found on Mauritius island. The last record of a living one is from 1681. Applied in Eng. to stupid persons since 1886.
mug (v.): "to beat up," 1818, originally "to strike the face" (in pugilism), from mug (n.2). The general meaning "attack" is first attested 1846, and "attack to rob" is from 1864 (mugger in this sense is from 1865). Perhaps influenced by thieves' slang mug "dupe, fool, sucker" (1851).
ninny: "simpleton, fool," 1593, perhaps a misdivision of an innocent, or from the pet form of the proper name Innocent, with sense influenced by the name's literal meaning. There may be some influence in the word of It. ninno "baby, child."
tomfool: "buffoon, clown," 1650, from M.E. Thom Foole, personification of a mentally deficient man (1338), see Tom + fool. Tomfoolery is recorded from 1812.
coax: 1580s, originally in slang phrase to make a coax of, from earlier noun coax, cox, cokes "a fool, ninny, simpleton;" modern spelling is 1706. Origin obscure, perhaps related to cock.
coot: c.1300, cote, used for various water fowl (now limited to Fulica atra and, in North America, F. americana), of uncertain origin (cf. Du. meercoet "lake coot"). Meaning "silly person, fool" is attested from 1766.
putz: "obnoxious man, fool," 1964, from Yiddish, from Ger. putz, lit. "finery, adornment," obviously used here in an ironic sense. Earlier in slang sense of "penis" (1934, in "Tropic of Cancer"); a non-ironic sense is in putz "Nativity display around a Christmas tree" (1902), from Pennsylvania Dutch.
patsy: "fall guy, victim of a deception," 1903, of unknown origin, possibly an alteration of It. pazzo "madman" (see patch (2)), or south It. dial. paccio "fool." Another theory traces it to Patsy Bolivar, character in an 1880s minstrel skit who was blamed whenever anything went wrong.
nincompoop: 1676, nicompoop. Despite similarity [noted by Johnson] to L. legal phrase non compos mentis "insane, mentally incompetent" (1607), the connection is denied by etymologists because the earliest forms lack the second -n-. Weekley thinks first element may be a proper name, and cites Nicodemus, which he says was used in Fr. for "a fool," or Nicholas.
loco: 1844, Amer.Eng., from Sp. loco (adj.) "insane," of uncertain origin, perhaps from Arabic lauqa, fem. of 'alwaq "fool, crazy person." Loco-weed (1879) was name given to species of western U.S. plants that cause cattle and horse diseases that make them stagger and act strangely.
folly: early 13c., from O.Fr. folie, from fol (see fool). Sense of "costly structure considered to have shown folly in the builder" is attested from 1650s. Used since M.E. of place names, especially country estates, as a form of O.Fr. folie in its meaning "delight." Meaning "glamorous theatrical revue with lots of pretty girls" is from 1880, from French.
geek: "sideshow freak," 1916, U.S. carnival and circus slang, perhaps a variant of geck "a fool, dupe, simpleton" (1515), apparently from Low Ger. geck, from an imitative verb found in North Sea Gmc. and Scand. meaning "to croak, cackle," and also "to mock, cheat." The modern form and the popular use with ref. to circus sideshow "wild men" is from 1946, in William Lindsay Gresham's novel "Nightmare Alley" (made into a film in 1947 starring Tyrone Power).
fob (v.): "to cheat," 1583, from obsolete noun fobbe "cheat, trickster" (1393), perhaps from O.Fr. forbe "cheat." Alternative etymology holds that the word is perhaps related to Ger. foppen "to jeer at, make a fool of" (see fop); or from Ger. fuppen, einfuppen "to pocket stealthily," which would connect it to fob (n.). To fob (someone) off is first recorded 1597.
moppet: 1601, "endearing term for a baby, a girl, etc.," from M.E. moppe "little child, baby doll" (c.1440) + -et, dim. suffix. The M.E. word also meant "simpleton, fool," and may have been cognate with Low Ger. mop "simpleton." Or, if "baby doll" is the original sense in M.E., perhaps from L. mappa "napkin, tablecloth," hence "rag doll."
infatuate: late 15c., from L. infatuatus, pp. of infatuare "make a fool of, infatuate," from in- "in" + fatuus "foolish."
sot: late O.E. sott "stupid person, fool," from O.Fr. sot, from Gallo-Romance *sott- (cf. M.L. sottus, c.800), of uncertain origin, with cognates from Portugal to Germany. Meaning "one who is stupefied with drink" first recorded 1590s. As a verb, it is attested from late 14c. (implied in sotted); besot "affect with a foolish manifestation" first recorded 1580.
wacky: "crazy, eccentric," 1935, variant of whacky (n.) "fool," late 1800s British slang, probably ultimately from whack "a blow, stroke," from the notion of being whacked on the head one too many times. Wack "crazy person" is a 1938 back-formation; extended form wacko is recorded from 1977. Wack in slang sense of "worthless, stupid," is attested from late 1990s.
baboon: type of ape, c.1400, babewyn, earlier "a grotesque figure used in architecture or decoration" (early 14c.), from Fr. babouin "baboon," from O.Fr. baboin "ape," earlier "simpleton, dimwit, fool" (13c.), also "gaping figure (such as a gargoyle)," so probably from O.Fr. baboue "grimacing;" or perhaps it is imitative of the ape's babbling speech-like cries. Ger. Pavian "baboon" is from Du. baviaan, from M.Du. baubijn, a borrowing of the O.Fr. word.
rib: O.E. ribb "rib," from P.Gmc. *rebja (cf. O.N. rif, O.Fris. ribb, O.H.G. ribba, Ger. Rippe), lit. "a covering" (of the chest), from PIE *rebh- "to roof, cover" (cf. O.C.S. rebro "rib"). The verb meaning "tease, fool" is first attested 1930, perhaps as a figurative extension of poking someone in the ribs. Rib joint "brothel" is slang from 1943, probably in allusion to Adam's rib (cf. rib "woman, wife," attested from 1589).
beast: early 13c., from O.Fr. beste (11c., Mod.Fr. bête) "animal, wild beast," figuratively "fool, idiot;" from L. bestia "beast, wild animal," of unknown origin. replacing O.E. deor (see deer) as the generic word for "wild creature," only to be ousted 16c. by animal.
dwell: O.E. dwellan "to mislead, deceive," originally "to make a fool of, lead astray," from P.Gmc. *dwaljanan (cf. O.N. dvöl "delay," dvali "sleep;" M.Du. dwellen "to stun, make giddy, perplex;" Dan. dvale "trance, stupor," dvaelbær "narcotic berry," source of M.E. dwale "nightshade"), from PIE *dhwel-. Related to O.E. gedweola "error, heresy, madness." Sense shifted in M.E. through "hinder, delay," to "linger" (c.1200, as still in phrase to dwell upon), to "make a home" (c.1250). Dwelling "place of residence" is attested from 1340.
shuck (v.): 1819, "to remove the shucks from," from noun (1674) meaning "husk, pod, shell," Amer.Eng., of unknown origin. Later used in ref. to the shells of oysters and clams (1872). Interjection shucks is 1847, from sense of "something valueless" (not worth shucks). Many extended senses are from the notion of "stripping" an ear of corn, or from the capers associated with husking frolics; e.g. "to strip (off) one's clothes" (1848) and "to deceive, swindle, cheat, fool" (1959); phrase shucking and jiving "fooling, deceiving" is suggested from 1966, in U.S. black English, but cf. shuck (v.) a slang term among "cool musicians" for "to improvise chords, esp. to a piece of music one does not know" (1957), and shuck (n.) "a theft or fraud," in use by 1950s among U.S. blacks.
"[B]lack senses probably fr[om] the fact that black slaves sang and shouted gleefully during corn-shucking season, and this behavior, along with lying and teasing, became a part of the protective and evasive behavior normally adopted towards white people in "traditional" race relations; the sense of "swindle" is perhaps related to the mid-1800s term to be shucked out, "be defeated, be denied victory," which suggests that the notion of stripping someone as an ear of corn is stripped may be basic in the semantics." ["Dictionary of American Slang"]
saint: early 12c., from O.Fr. seinte, altering O.E. sanct, both from L. sanctus "holy, consecrated" (used as a noun in L.L.), prop. pp. of sancire "consecrate" (see sacred). Adopted into most Gmc. languages (cf. O.Fris. sankt, Du. sint, Ger. Sanct). Originally an adj. prefixed to the name of a canonized person; by c.1300 it came to be regarded as a noun.
"Saint - A dead sinner revised and edited. The Duchess of Orleans relates that the irreverent old calumniator, Marshal Villeroi, who in his youth had known St. Francis de Sales, said, on hearing him called saint: 'I am delighted to hear that Monsieur de Sales is a saint. He was fond of saying indelicate things, and used to cheat at cards. In other respects he was a perfect gentleman, though a fool.' " [Ambrose Bierce, "Devil's Dictionary," 1911]
Meaning "person of extraordinary holiness" is recorded from 1563. The verb meaning "to enroll (someone) among the saints" is attested from late 14c. Applied widely to living things, diseases, objects and phenomena, e.g. Saint Bernard, the breed of mastiff dogs (1839), so called because they were used by the monks of the hospice of the pass of St. Bernard (between Italy and Switzerland) to rescue snowbound travelers; St. Elmo's Fire "corposant" (1560s) is from It. fuoco di Sant'Elmo, named for the patron saint of Mediterranean sailors, a corruption of the name of St. Erasmus, an Italian bishop martyred in 303.
nigger: 1786, earlier neger (1568, Scot. and northern England dialect), from Fr. nègre, from Sp. negro (see Negro). From the earliest usage it was "the term that carries with it all the obloquy and contempt and rejection which whites have inflicted on blacks" [cited in Gowers, 1965]. But as black inferiority was at one time a near universal assumption in Eng.-speaking lands, the word in some cases could be used without deliberate insult. More sympathetic writers late 18c. and early 19c. seem to have used black (n.) and, after the American Civil War, colored person. Also applied by Eng. settlers to dark-skinned native peoples in India, Australia, Polynesia. The reclamation of the word as a neutral or positive term in black culture, often with a suggestion of "soul" or "style," is attested first in the Amer. South, later (1968) in the Northern, urban-based Black Power movement. Variant niggah, attested from 1925 (without the -h, from 1969), is found usually in situations where blacks use the word. Nigra (1944), on the other hand, reflects a pronunciation in certain circles of Negro, but meant to suggest nigger, and is thus deemed (according to a 1960 slang dictionary) "even more derog. than 'nigger.' " Slang phrase nigger in the woodpile attested by 1800; "A mode of accounting for the disappearance of fuel; an unsolved mystery" [R.H. Thornton, "American Glossary," 1912]. Nigger heaven, "the top gallery in a (segregated) theater" first attested 1878 in ref. to Troy, N.Y.
" 'You're a fool nigger, and the worst day's work Pa ever did was to buy you,' said Scarlett slowly. ... There, she thought, I've said 'nigger' and Mother wouldn't like that at all." [Margaret Mitchell, "Gone With the Wind," 1936]
Used in combinations (e.g. nigger-brown, nigger-head, nigger-toe) since 1840s for various dark brown or black hues or objects; euphemistic substitutions (e.g. Zulu) began to appear in these senses c.1917.