Green’s Dictionary of Slang

1. a short, squat person.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1848		Bartlett Dict. Americanisms.
1859		Hotten Dict. of Modern Sl. etc. 52: HUMPTY DUMPTY, short and thick.
1860		Hotten Dict. of Modern Sl. etc. [as cit. 1859].
1873		Sl. Dict.

2. a hunchback.

1873

Sl. Dict. 198: Humpty-dumpty [...] a hunchback.

3. (US, also humpty) an outright failure, an incompetent person, esp. in sport.

1924		H.L. Wilson Professor How Could You! 266: He plays the piano with Reddick, and he’s some Humpty-Dumpty on it.
1936		J. Curtis Gilt Kid 246: Bloody fool to have panicked. Trying to run. Made a dead tumble out of it. A regular humpty dumpty.
1952		W.R. Burnett Little Men, Big World 19: What humpty-dumpties! [...] This big hitter they got—I saw him bust one up against the fence in the far right corner and only get a single.
1972		R. Kahn Boys of Summer 235: ‘I was struggling so much I couldn’t enjoy it. Snider, Pafko, Furillo, they weren’t humpties. [...] To play with guys that good was humbling’.
1973		S. Ace Stand On It (1979) 154: Man, those humpties and hayshakers all over the South just love demolition derbies.
1975		(con. 1930s) Durocher & Linn Nice Guys Finish Last 45: Babe Ruth was waiting to hit [...] ‘Get out of here, you humpty-dumpty,’ he roared.