Green’s Dictionary of Slang

1. a hit, a blow.

1884		Sporting Times 13 Dec. 1/3: A slosh on the earhole with a bootjack will stop the loudest-voiced vendor of journals.
1904		in W.C. Fields By Himself (1974) 24: A certain eccentric [...] got an awful slosh in the puss.
1912		Sport (Adelaide) 7 Dec. 13/2: They Say [...] That Slosh [i.e. a batsman] had two big ‘hits and misses’ [...] and puts it down to a wet wicket.
1914		R. Tressell Ragged Trousered Philanthropists (1955) 450: I ups with me fist an’ I gives ’im a slosh in the dial.
1919		Marvel 3 Mar. 6: My slosh was nothing, Fane, old top [...] I was asking for it when I got it.
1922		Wodehouse Clicking of Cuthbert 40: A woman is only a woman, but a hefty drive is a slosh.
1939		Wodehouse Uncle Fred in the Springtime 194: ‘[G]iving you the slosh on the jaw which you have been asking for with every word you have uttered’.
1950		C. Harris Three-Ha’Pence to the Angel 33: Bim my old man, I’d ’ave ’ad a good slosh round the jaw before you could say ninepence.
1953		J. Franklyn Cockney 266: That there young ’Arry Noakes don’t ’arf want a slosh around the clock!
1960		A. Burgess Doctor Is Sick (1972) 199: Bob administered a token backhanded slosh on the nose.

2. an attempt at hitting.

1958

Willans & Searle Complete Molesworth (1985) 160: I usually prefer to hav a slosh: i get bowled just the same.