Green’s Dictionary of Slang

(WW II/Aus.) whisky.

1941		‘Rows and Rows and Rows’ in C.H. Ward-Jackson Airman’s Song Book (1945) 140: Wherever there’s a bottle or a chota drop of ‘ski’.
1952		T.A.G. Hungerford Ridge and River (1966) 3: What’s more, Little Lord Lovatt’ll be there, too. With a bottle of ski at his elbow.
1984		Partridge DSUE (8th edn) 1077/1: ski Whisky WW2. [Ibid.] 1081/1: sky whisky Aus. since ca. 1950.