Green’s Dictionary of Slang

1. a fool; thus gump-headed, foolish.

1825		J. Neal Brother Jonathan II 42: He’s your brother, I guess? [...] sort of a naiteral too, I guess; rather a gump, hey?
1833		A. Greene Life and Adventures of Dr Dodimus Duckworth II 13: I pronounce you to be a gump, and no doctor.
1848		J.R. Lowell Biglow Papers (1880) 6: An’ it makes a handy sum, tu, / Any gump could larn by heart.
c.1850		F.M. Whitcher Widow Bedott Papers (1883) 32: He’s the consarndest old gump tew ’t ever was.
1866–1930		in Scot. National Dict.
1888		Advance (Chicago) 21 June 387: Molly, [...] has that great gump been making love to you?
1898		E.N. Westcott David Harum 216: You needn’t make me out more of a gump ’n I was.
1899		Notts. Guardian 21 Oct. 6/3: You a judge! You great gumph.
1907		W.M. Raine Bucky O’Connor (1910) 157: And do you think you’re fit to run even a donation party, you great, blundering gumph?
1913–14		E. O’Neill Warnings in Ten ‘Lost’ Plays (1995) 79: You ought to be ashamed of yourself, you big gump.
1915		S. Ford Shorty McCabe on the Job 278: You was sittin’ there like a gump.
1926		J. Tully Jarnegan (1928) 175: The poor little gump.
1926		Weston & Lee [perf. Bromley Carter] ‘Bachelor Ben’ 🎵 My married friends laugh and declare I’m a chump / But when I see their wives, I think,‘Umph! I’m no gump’.
1927		C. Sandburg ‘Common Bill’ in Amer. Songbag 63: I began to think the gump-head / Would never go away.
1936		M. Levin Old Bunch (1946) 12: Oh, don’t be a gump.
1940		M. Marples Public School Slang 59: Boys in general have a great flair for derogatory and vituperative expression [...] swot, swank, sneak, jew, swine, tick, scoff, cad, blog, nip, oik, lout, wet, drip, squit, squirt, mug, scug, sap, simp, seet, gump, muff, goof, goop, waft.
1963		A. Baron Lowlife (2001) 74: He believed me, poor goomp.
1997–2001		Online Sl. Dict. 🌐 gump n 1. a tall clumsy person.

2. (US ) nonsensical or cheeky talk.

1913		J. London Valley of the Moon (1914) 415: There are a million boys in our public schools right now swallowing the gump of canal boy to President.
1992		R.C. Cruz Straight Outta Compton 64: He wasn’t about to take any gump from a so-and-so self-proclaimed homicide officer who had done the nasty with a white girl.

3. (US prison) a passive homosexual, the target of predatory prison homosexuals.

1981		Maledicta V:1+2 (Summer + Winter) 265: An aggressive homosexual, a jocker, forces himself upon a gump, a passive homosexual, or a punk, a weak person used for sex.
1991		C. Fletcher Pure Cop 106: Gumps are also known as ‘he/she’s’. But actually, in their terminology, they’re queens. And their code is ‘We special girls’.
2000		Other Side of the Wall: Prisoner’s Dict. July 🌐 Gump: Homosexual. (VA).