Green’s Dictionary of Slang

1. simple, stupid.

1984

Partridge DSUE (8th edn) 523/1: late C.19–early 20.

2. drunk.

1741		Garrick Lying Valet II i: She got so very gay after dinner, she could not walk out of her own house; so her maid, who was half gone too, came here with an excuse.
1830		W. Carleton ‘The Hedge School’ in Traits and Stories of Irish Peasantry I (1868) 272: As for Mat, when he’s half gone, I’d turn him agin the country for deepness in larning; for it’s then he rhymes it out of him.
1833		Satirist (London) 17 Mar. 509/3: ‘Dam de debbel!’ cried Rotchy, ‘half gone,’ at the Jerusalem [Tavern].
1906		Salt Lake City (UT) 30 Mar. 4/5: He is [...] half-shot, half-gone .
1964		P. Terson Night to Make the Angels Weep (1967) II xi: Chairmen’s secretaries, models, society women. Bare shoulders. Coiffures up. Most of them half gone.

3. (US milit.) hungry.

1940		Phila. Eve. Ledger 20 July n.p.: ‘Half gone’--to be hungry.
1944		P. Kendall Dict. Service Sl. n.p.: half gone . . . hungry.