Green’s Dictionary of Slang

1. drunk to the extent of nearly or actually falling over.

1884		Sporting Times 15 Nov. 1/2: ‘’Ave tonic?’ said the Roman [...] ‘my tonic is perfectly ’armless.’ ‘It generally,’ replied the Shifter [...] ‘leaves me perfectly legless’.
1926		J. Black You Can’t Win (2000) 149: She poured liquor into the bums, beggars, ragtags and bobtails that hung around the saloons till they were legless drunk.
1930		J. Black ‘A Burglar Looks at Laws and Codes’ in Harper’s Mag. CLX 307: He [...] discovered his helper legless drunk.
c.1940–5		‘Myles na gCopaleen’ Best of Myles (1968) 338: Drunk; jarred; [...] full to the brim; footless; blind.
1965		L. Dunne Goodbye to The Hill (1966) 143: Breeda had a terrific supply of gargle in the flat and we both got footless by about ten o’clock.
1977		P. O’Farrell Book of Irish Farmers’ Jokes 44: Her little daughter ran into the kitchen shouting that her daddy was back from his visit to the chiropodist and that he was footless.
1979		F. Norman Too Many Crooks Spoil the Caper 37: Maybe if they got legless before I did, they’d let slip why they’d entered into competition with Willy to gain possession of it.
1984		‘Derek Raymond’ He Died with His Eyes Open 71: He said no, he liked it here, and kept coming back legless.
1995		A. Higgins Donkey’s Years 129: Even if he was footless with the drink?
1996		P. Temple Bad Debts (2012) [ebook] A bloke that’s so legless that he’s passed out.
1999		N. Cohn Yes We have No 129: One night, legless, she started acting up.
2008		Islington N.H.S. anti-drinking campaign poster Dec.: Blotto, hammered, legless, plastered, smashed, wasted . . . whatever you call it, don’t let the Christmas spirit make a fool of you!
2016		N. Cummins Adventures of the Honey Badger [ebook] VITAL AUSSIE VERNACULAR Drunk: 1. Full 2. Legless 3. Lubricated 4. Pissed as a fart.
2017		M. Forsyth Short History of Drunkenness 40: They liked to get legless.
2024		J. Meades Empty Wigs (t/s) 910: [H]e is legless as legend air-ace.

2. exhausted.

1999

Observer Rev. 30 May 2: Three hours later, legless with inanition [...] we finally climbed on board.