Green’s Dictionary of Slang

(US) a drink.

1899		Sun (NY) 5 Mar. 25/1: I walked [...] wondering how I could get just one hooter to make me feel that life would be worth living.
1899		B.W. Green Virginia Folk-Speech 191: Hooter, n. A dram; a drink; from, tin cup from which the drink was taken [DARE].
1899–1900		C.L. Cullen Tales of the Ex-Tanks 105: We might take a hooter or two, we admitted.
1907		News & Courier (Charleston, SC) 14 Apr. 18/2: Give me a hooter of the red kind.