Why is the ninth month called September?
mid-14c., gunne "an engine of war that throws rocks, arrows or other missiles," probably a shortening of woman's name Gunilda, found in Middle English gonnilde "cannon" and in an Anglo-Latin reference to a specific gun from a 1330 munitions inventory of Windsor Castle ("...una magna balista de cornu quae Domina Gunilda ..."), from Old Norse Gunnhildr, woman's name, from gunnr + hildr, both meaning "war, battle." First element from PIE *gwhen- "to strike, kill" (see bane); for second, cf. Hilda.
The identification of women with powerful weapons is common historically (cf. Big Bertha, Brown Bess, Mons Meg, etc.); meaning shifted with technology, from cannons to firearms as they developed 15c. Great guns (cannon, etc.) distinguished from small guns (such as muskets) from c.1400. Applied to pistols and revolvers after 1744. Meaning "thief, rascal" is from 1858. Son of a gun is originally nautical. To jump the gun (1912, American English) is from track and field. Guns "a woman's breasts" (especially if prominent) attested by 2006.
"to shoot with a gun," 1620s, from gun (n.); the sense of "to accelerate an engine" is from 1930, from earlier phrase to give (something) the gun. Related: Gunned; gunning.
"type of distilled drinking alcohol," 1714, shortening of geneva, altered (by influence of the similarity of the name of the Swiss city, with which it has no other connection) from Dutch genever "juniper" (because the alcohol was flavored with its berries), from Old French genevre, from Vulgar Latin *jeniperus, from Latin juniperus "juniper" (see juniper). Gin and tonic attested by 1873; gin-sling by 1790. Card game gin rummy first attested 1941 (described in "Life" that year as the latest Hollywood fad).
"machine for separating cotton from seeds," 1796, American English, used earlier of various other machineries, from Middle English gin "ingenious device, contrivance" (c.1200), from Old French gin "machine, device, scheme," shortened form of engin, from Latin ingenium (see engine). The verb in this sense is recorded from 1789.
in slang phrase gin up "enliven, make more exciting," 1887, probably from earlier ginger up in same sense (1849), from ginger in sense of "spice, pizzazz;" specifically in reference to the treatment described in the 1811 slang dictionary under the entry for feague:
... to put ginger up a horse's fundament, and formerly, as it is said, a live eel, to make him lively and carry his tail well; it is said, a forfeit is incurred by any horse-dealer's servant, who shall shew a horse without first feaguing him. Feague is used, figuratively, for encouraging or spiriting one up.
"to begin," c.1200, ginnen, shortened form of beginnen (see begin).
(also gon) A professional thief, esp a pickpocket
[1858+; fr Yiddish gonif]
a trap. (1.) Ps. 140:5, 141:9, Amos 3:5, the Hebrew word used, _mokesh_, means a noose or "snare," as it is elsewhere rendered (Ps. 18:5; Prov. 13:14, etc.). (2.) Job 18:9, Isa. 8:14, Heb. pah, a plate or thin layer; and hence a net, a snare, trap, especially of a fowler (Ps. 69: 22, "Let their table before them become a net;" Amos 3:5, "Doth a bird fall into a net [pah] upon the ground where there is no trap-stick [mokesh] for her? doth the net [pah] spring up from the ground and take nothing at all?", Gesenius.)