"iron hook," c. 1300, gaffe, from Old French gaffe "boat hook" (see gaffe). Specifically of the hook on a fishing spear from 1650s. As a type of spar from 1769. Related: gaff-hook.

"talk," 1812, in phrase blow the gaff "spill a secret," of uncertain origin. OED points out Old English gafspræc "blasphemous or ribald speech," and Scottish gaff "loud, rude talk" (by 1825). Compare gaffe.

1580s, "elderly rustic," apparently (based on continental analogies) a contraction of godfather (compare gammer). Originally a term of respect, also applied familiarly; from "old man" it was extended by 1841 to foremen and supervisors, which sense carried over in early 20c. to "electrician in charge of lighting on a film set."

mid-15c., transitive, "to choke, strangle" (someone), possibly imitative and perhaps influenced by Old Norse gag-hals "with head thrown back." The sense of "stop a person's mouth by thrusting something into it" is first attested c. 1500. Intransitive sense of "to retch" is from 1707. Transitive meaning "cause to heave with nausea" is from 1945. Related: Gagged; gagging.

"a joke," 1863, especially a practical joke, probably related to theatrical sense of "matter interpolated in a written piece by the actor" (1847); or from the sense "made-up story" (1805); or from slang verbal sense of "to deceive, take in with talk" (1777), all of which perhaps are from gag (v.) on the notion of "to stuff, fill." Gagster "comedian" is by 1932.

"something thrust into the mouth or throat to prevent speaking," 1550s, from gag (v.); figurative use, "violent or authoritative repression of speech," is from 1620s. Gag-law in reference to curbs on freedom of the press is from 1798, American English. The gag-rule that blocked anti-slavery petitions in the U.S. House of Representatives was in force from 1836 to 1844.

"crazy, silly," 1920, probably from French gaga "senile, foolish," probably imitative of meaningless babbling.

c. 1400, "to deposit as security," from Old French gager, gagier "to guarantee, promise, pledge, swear; bet, wager; pay," from gage "security, pledge" (see gage (n.)). Related: Gaged; gaging. For the measuring sense, see gauge (v.).

"a pledge, a pawn, something valuable deposited to insure performance," especially "something thrown down as a token of challenge," c. 1300, from Old French gage "pledge (of battle), security, guarantee; pay, reward" (11c.), from Frankish *wadja-, from Proto-Germanic *wadi- (see wed). Italian gaggio, Spanish and Portuguese gage are French loan-words.

late 15c., gagyll, with reference to both geese and women (on the notion of "chattering company"). Barnhart says possibly from Old Norse gagl "small goose, gosling, wild goose;" OED calls it "one of the many artificial terms invented in the 15th c. as distinctive collectives referring to particular animals or classes of persons." Possibly of imitative origin (compare Dutch gagelen "to chatter;" Middle English gaggle "to cackle," used of geese, attested from late 14c.). The loosened general sense of "group of people" is from 1946.