gullible (adj.)
1825, apparently a back-formation from gullibility. Gullable is attested from 1818.
Gulliver
male proper name, from Old French goulafre "glutton," a very common name, found as a surname in Domesday Book (William Gulafra).
gully (n.)
"channel made by running water," 1650s, possibly a variant of Middle English golet "water channel" (see gullet). Gully-washer, American English colloquial for "heavy rainstorm," attested by 1887.
gulp (v.)
late 14c., a native coinage or else from Flemish gulpe or Dutch gulpen "to gush, pour forth, guzzle, swallow," in any case possibly of imitative origin (compare Swedish dialectal glapa "to gulp down"). Related: Gulped; gulping.
gulp (n.)
1560s, from gulp (v.), or else from Flemish gulpe, Dutch gulp "stream of water, large draught."
gum (n.1)
"resin," c.1300, from Old French gome "(medicinal) gum, resin," from Late Latin gumma, from Latin gummi, from Greek kommi "gum," from Egyptian kemai. As a shortened form of chewing gum, first attested 1842 in American English. The gum tree (1670s) was so called for the resin it exudes.
gum (n.2)
"membranes of the mouth," Old English goma "palate, side of the mouth" (single or plural), from a Germanic source represented by Old Norse gomi "palate," Old High German goumo; related to Lithuanian gomurys "palate," and perhaps from PIE *gheu- "to yawn" (source also of Greek khaos; see chaos).
gum (v.)
early 14c., gommen, "treat with (medicinal or aromatic) gums," from gum (n.1). In the transferred or figurative sense of "spoil, ruin" (usually with up), it is first recorded 1901, probably from the notion of machinery becoming clogged. Of infants, etc., "to chew or gnaw (something) with the gums," by 1907, from gum (n.2). Related: Gummed; gumming.
gumbo
1805, from Louisiana French, probably ultimately from Central Bantu dialect (compare Mbundu ngombo "okra").
gummy
late 14c., from gum (n.1) + -y (2). Related: Gumminess.
gump (n.)
"dolt, numskull," 1825; meaning "chicken" is from 1914, U.S. thieves' slang.
gumption (n.)
1719, originally Scottish, "common sense, shrewdness," also "drive, initiative," possibly connected with Middle English gome "attention, heed," from Old Norse gaumr "heed, attention." Sense of "initiative" is first recorded 1812.
gumshoe (n.)
"plainclothes detective," 1906, from the rubber-soled shoes they wore (which were so called from 1863); from gum (n.1) + shoe (n.).
gun (n.)
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, see Hilda.

The identification of women with powerful weapons is common historically (such as 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. For son of a gun, see son. To jump the gun (1912, American English) is from track and field. Guns "a woman's breasts" (especially if prominent) attested by 2006.
gun (v.)
"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.
gun moll
1908, "female criminal," second element from nickname of Mary, used of disreputable females since early 1600s; first element from slang gonif "thief" (1885), from Yiddish, from Hebrew gannabh "thief."
gun-metal
commonly an alloy of copper and zinc; used attributively of a dull blue-gray color since 1905.
gun-shy (adj.)
1884, originally of sporting dogs, from gun (n.) + shy (adj.).
gunboat
1793, from gun + boat. Gunboat diplomacy is from 1916, originally with reference to Western policies in China.
gung ho
also gung-ho, gungho, 1942, slang motto of Carlson's Raiders (2nd Marine Raider Battalion, under Lt. Col. Evans Carlson, 1896-1947), U.S. guerrilla unit operating in the Pacific in World War II, from Chinese kung ho "work together, cooperate." Widely adopted in American English c.1959.
Borrowing an idea from China, Carlson frequently has what he calls 'kung-hou' meetings .... Problems are threshed out and orders explained. ["New York Times Magazine," Nov. 8, 1942]
gunk (n.)
1949, "viscous substance," American English, apparently from Gunk, trademark for a thick liquid soap patented 1932 by A.F. Curran Co. of Malden, Mass.
gunman (n.)
1620s, from gun (n.) + man (n.). In early American English use, especially of Indian warriors.
gunnel (n.)
small marine fish, 1680s, of unknown origin; perhaps from Cornish.
gunner (n.)
mid-14c., gonner "one who works a cannon," agent noun from gun.
gunnery (n.)
c.1600, from gun + -ery.
gunny (n.)
1711, Anglo-Indian goney "coarse fabric," from Hindi goni, from Sanskrit goni "sack." Gunny sack attested by 1862.
gunplay (n.)
also gun-play, 1891, from gun (n.) + play (n.).
gunpowder (n.)
early 15c., from gun (n.) + powder (n.). The Gunpowder Plot was the conspiracy to blow up the Houses of Parliament on Nov. 5, 1605, while the King, Lords and Commons were assembled there.
gunsel (n.)
1914, American English, from hobo slang, "a catamite;" specifically "a young male kept as a sexual companion, especially by an older tramp," from Yiddish genzel, from German Gänslein "gosling, young goose." The secondary, non-sexual meaning "young hoodlum" seems to be entirely traceable to Dashiell Hammett, who sneaked it into "The Maltese Falcon" (1929) while warring with his editor over the book's racy language.
"Another thing," Spade repeated, glaring at the boy: "Keep that gunsel away from me while you're making up your mind. I'll kill him."
The context implies some connection with gun and a sense of "gunman," and evidently the editor bought it. The word was retained in the script of the 1941 movie made from the book, so evidently the Motion Picture Production Code censors didn't know it either.
The relationship between Kasper Gutman (Sidney Greenstreet) and his young hit-man companion, Wilmer Cook (Elisha Cook, Jr.), is made fairly clear in the movie, but the overt mention of sexual perversion would have been deleted if the censors hadn't made the same mistaken assumption as Hammett's editor. [Hugh Rawson, "Wicked Words," 1989, p.184]
gunshot (n.)
early 15c., "shot fired from a gun," from gun (n.) + shot (n.). Meaning "range of a gun or cannon" is from 1530s.
gunsmith (n.)
1580s, from gun (n.) + smith.
Gunther
also Gunter, masc. proper name, Old High German Gundhard, literally "bold in war," from gund "war" (see gun) + hart "hard, strong, bold" (see hard).
gunwale (n.)
mid-15c., gonne walle, from gun (n.) + wale "plank" (see wale). Originally a platform on the deck of a ship to support the mounted guns.
guppy (n.)
1925, named for R.J.L. Guppy, Trinidad clergyman who supplied the first specimen (1866) to the British Museum. The family name is from a place in Dorset. The class of streamlined U.S. submarines (1948) is an acronym from greater underwater propulsion power + -y.
Gupta
4c.-6c. North Indian dynasty, from Chandragupta, name of the founder.
gurges (n.)
1660s, from Latin gurges, literally "whirlpool," from PIE *gwrg-, reduplicated form of root *gwere- (4) "to swallow" (see voracity).
gurgitation (n.)
late 14c., from Late Latin gurgulationem (nominative gurgulatio), noun of action from past participle stem of gurgitare "to engulf," from gurges "whirlpool, gorge" (see gurges).
gurgle (v.)
early 15c., medical term for "gurgling heard in the abdomen," a native, echoic formation, or ultimately from Latin gurguliare, perhaps via Dutch, German gurgeln. Extended (non-anatomical) use, in reference to water over stones, etc., is first recorded 1713. "This phenomenon of long specialized use before becoming a part of the general vocabulary is often found in English" [Barnhart]. Related: Gurgled; gurgling. As a noun from early 15c.
Gurkha
1811, member of a dominant race of Nepal, of Hindu descent, famous as warriors. Said to be ultimately from Sanskrit gauh "cow" + raksati "he protects."
gurnard (n.)
small marine fish, early 14c., from Old French gournart (13c.), formed by metathesis of gronir, from Latin grunire "to grunt." The fish so called for the sound it makes when pulled from the water.
gurney (n.)
by 1921, of unknown origin. It also is a surname.
guru (n.)
1800, gooroo, from Hindi guru "teacher, priest," from Sanskrit guru-s "one to be honored, teacher," literally "heavy, weighty," from PIE root *gru- (see grave (adj.)). Generalized sense of "mentor" is from 1940; sense of "expert in something" first recorded c.1966 in Canadian English in reference to Marshall McLuhan.
gush (v.)
12c., gosshien "make noises in the stomach," later (c.1400) "rush out suddenly, pour out," probably formed imitativeally in English under influence of Old Norse gusa "to gush, spurt," related to geyser. Metaphoric sense of "speak in an effusive manner" first recorded 1873. Related: Gushed; gushing. The noun is 1680s, from the verb.
gusher (n.)
"oil well that flows without pumping," 1886, agent noun from gush. Earlier in a sense of "overly effusive person" (1864).
gushy (adj.)
1845, from gush in the metaphoric sense + -y (2). Related: Gushily; gushiness.
gusset (n.)
early 14c., from Old French gosset "armpit; piece of armor for the armpit" (13c.), apparently from gousse "shell of a nut," of unknown origin. Originally an armorer's term; of clothing from 1560s.
gussy (v.)
"to dress up or decorate in a showy way," 1952, American English slang, apparently from Gussy (1940), schoolyard slang name for an overly dressed person, perhaps related to gussie (1901) "effeminate man," and somehow connected to the nickname for Augusta and Augustus.
gust (n.)
1580s, possibly a dialectal survival from Old Norse gustr "a cold blast of wind" (related to gusa "to gush, spurt") or Old High German gussa "flood," both from Proto-Germanic *gustiz, from PIE *gheus-, from root *gheu- "to pour" (see found (2)). Probably originally in English as a nautical term. As a verb, from 1813. Related: Gusted; gusting.
gustation (n.)
"act of tasting," 1590s, from Latin gustationem (nominative gustatio), noun of action from past participle stem of gustare "to taste" (see gusto).
gustatory (adj.)
1680s, from Latin gustatus "sense of taste; a taste," noun use of past participle of gustare "to taste" (see gusto) + -ory.