Green’s Dictionary of Slang

1. tea.

1719		in D’Urfey Pills to Purge Melancholy IV 204: They’re Fools who use Washes, / when Claret’s at hand.
1858		A. Mayhew Paved with Gold 372: D—n tea! [...] it’s only child’s wash at the best. It drowns a man’s nature.
1894		Daily News 8 Sept. 6/3: He calls his tea ‘snoodle’ or wash’ .
1914		Laverton Mercury (WA) 31 Oct. 3/7: Tea is referred to as ‘wash,’ cocoa as ‘push’ .

2. beer, also as an accompaniment to a spirit.

1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor III 255/2: If we could get the genuine home-brewed, that would be the stuff to do us good; the publican’s wash is no good.
1866		Border Watch (Mt Gambier, SA) 31 Oct. 3/2: THE LATEST SLANG CREATION IN NEW YORK [...] A fast young man when thirsty-asks for a ‘wash’.
1926		J. Tully Jarnegan (1928) 56: Give me some liquor – no wash ... I’ll take her straight.
1956		N. Algren Walk on the Wild Side 277: ‘What are you having yourself?’ ‘Whiskey and wash.’ [...] Dove poured his whiskey into his beer, taking his time with the pouring.
1974		C. Loken Come Monday Morning 35: Gimme another – hold the wash.

3. (US) a second or subsequent drink, one to ‘wash down’ that or those that have been consumed.

1880		Nat. Police Gaz. (NY) 25 Dec. 7/2: ‘Is there any of that ticker left, Mike?’ ‘It’s good for a round yet, Jess.’ ‘Start it then and give the colored delegation a wash’.
1951		R. Bissell Stretch on the River 139: What for a wash?

4. (Aus.) a tea-party.

1890

Bulletin (Sydney) 5 July 6/3: A Sydney Anglican parson bitterly complains in re the collection at his church, one of the largest and most important in the city. The wash on a recent Sunday panned out thus: [...].

5. (US) soda water.

1947

F. Brown Fabulous Clipjoint (1949) 146: The bartender spun a shot glass expertly along the bar and filled it from an Old Overholt bottle. ‘Wash?’ ‘Plain water,’ I told him.

6. (W.I.) the mash of cheap grain and sugar that is distilled to produce the homemade spirit sold in illicit drinking clubs [SE wash, malt etc. steeped in water to undergo fermentation].

1977		D. Powis Signs of Crime 207: Wash, the Shebeen proprietors’ term for the mash of cheap grain and sugar (for example) cooked before distillation into illegal drinking spirit alcohol. Has a very distinctive and repulsive super-sweet smell.
1990		in Lalla & D’Costa Lang. in Exile 104: Lexicon items JC [Jamaican creole] shares with both modern Krio and Guinea Coast Creole English of the 17th & 18th centuries are [...] pikin, JC pikni [...] was-mot (‘liquor’), JC wash-mout (‘early morning tea’).

7. (US drugs) a mix of heroin, water and blood that is injected by the user.

1974

V.E. Smith Jones Men 21: How’s the wash?

8. crack cocaine [the process of chemical purification, known as ‘washing’, that is used when making the drug].

2002		‘Drug Sl. Vault’ on Erowid.org 🌐 Wash Crack.
2018		Digga D ‘Mad About Bars’ 🎵 Little bro don’t know how to whip, he wants white wash.

9. see whitewash n. (2)