Green’s Dictionary of Slang

all out adj.

exhausted.

[1835		G. Kent Modern Flash Dict. 3: All out, the reckoning drank out, ‘How stands the account ’twixt me and vengeance’].
1843		N.Y. Sporting Whip 4 Feb. n.p.: Old Burke was, to use a piece of vulgar slang, ‘all out’.
1865		Sporting Gaz. (London) 1 Apr. 5/1: All out — with nothing left in him [i.e. a racehorse].
1901		Bulletin (Sydney) 7 Sept. 14/2: Witnessed [...] a full-grown wild emu pursuing a forlorn young calf. Emu, with a good bit in hand, was about half a length behind, while the calf was ‘all out’ and bellowing dismally.
1905		H. Green Actors’ Boarding House (1906) 249: He was all out and sleeping on top of the barrels.
1924		G.H. Lawson Dict. of Aus. Words And Terms 🌐 OUT, ALL — Exhausted.
1943		Mass-Observation Report on Juvenile Drinking 11: By this time the American looks as if he’s all out. The girl looks pretty red in the face.