Green’s Dictionary of Slang

(mainly UK tramp) beer, alcohol.

1908		W.H. Davies Autobiog. of a Super-Tramp 211: I seldom lie down at night but what I am half skimished (half drunk), for I assure you I never go short of my skimish.
1926		W.H. Davies Adventures of Johnny Walker 190: The wandering beggar says ‘skimish’ for drink, but the city beggar says ‘bouse’.
1935		Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks 10: Skirmish: Drink.
1936		J. Curtis Gilt Kid 40: He had been drinking all that skimish without having had a bite to eat.
1950		P. Hoskins No Hiding Place! 192/1: Skimish. Beer.
1977		D. Powis Signs of Crime 201: Skimmish Beer.