Green’s Dictionary of Slang

1. (also whack out, whack up) to share or divide equally; thus whack the blunt v., to share out the money; whacking n., a division, a share-out.

c.1790		Dublin Baker [broadsheet ballad] I wish’d them good night and sat down to cheir [i.e. cheer, food], / [I] whack’d the spoil with my comrad dear.
1812		Vaux Vocab. of the Flash Lang.
1821		D. Haggart Autobiog. 41: I whack’t the smash between Bagrie and Paterson, but kept none to myself.
1837		‘Now!’ in Rum Ti Tum! in Spedding & Watt (eds) Bawdy Songbooks (2011) III 170: Altogether in a bunch our alls ve’ll whack.
1842		Whip & Satirist of NY & Brooklyn (NY) 14 May n.p.: After they had whacked each other [...] agreed to whack the rowdy.
1845		Bell’s Life in Sydney 27 Sept. 3/2: It was mutually agreed to whack the blunt between them.
1849		‘Epistle from Joe Muggins’s Dog’ in Era (London) 12 Aug. 3/3: [I]f ther Scott and Day parties didn't lay their heds together to ‘wack it’ atween ’em, never beleeve me agen. ’Twas hevident they'd squared it.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor II 154/2: Long J-- and I got to quarrel about the ‘whacking;’ there was cheatin’ a goin’ on; it wasn’t all fair and above board.
1861		Bell’s Life in Sydney 2 Mar. 3/3: If she would wait while she ran to her ‘uncle’s’ she would on her return ’whack the ready’.
1865		Leaves from Diary of Celebrated Burglar 69/1: The ‘sugar was whacked,’ and after a ‘shant’ or two with the ‘cop’ we parted from him.
1883		‘The Jolly Vaquero’ in Lingenfelter et al. Songs of the Amer. West (1968) 337: He’ll ‘wack up’ his blankets, or share his ‘grub.’.
1885		Bulletin (Sydney) 17 Jan. 6/4: [A]lthough the Queen would never have dreamt of marrying him, still she is far-seeing, and, naturally, would have no objection to find his fortune whacked amongst her poor little boys and girls.
1888		‘Rolf Boldrewood’ Robbery Under Arms (1922) 82: He cashed the cheques and drew the lot in notes and gold [...] and then we ‘whacked’ the lot.
1894		Truth (Sydney) 11 Mar. 4/5: Many eminent solicitors [...] whacked the plunder with Jabez [Balfour]. Eminent chartered accountants ditto.
1896		G.F. Northall Warwickshire Word-Book 263: Whack. To divide, share.
1896		Dubbo Liberal (NSW) 17 June 3/3: But terror wasn’t half so bad, / When ‘whacked’ amongst the three.
1900		Bulletin (Sydney) 26 May 14/2: The same officer [...] mentioned that one of the blackfellows is married to a white woman, who buys the stuff – they drink crude wine most – and whacks it with her lord.
1915		C.E.W. Bean Anzac Book 101: For they’d whacked the Fray Bentos among them, / And each man had perished from thirst.
1928		(con. WWI) ‘Taffrail’ ‘A Little Drop o’ Leaf’ in Little Ship 243: Th’ orficer wants a bit o’ bacca out o’ your bundle. I whacked it out to the last bloke.
1930		(con. 1914–18) Brophy & Partridge Songs and Sl. of the British Soldier 177: Whack Out. — Variation of Dish-out.
1950		Goldin et al. DAUL 235/2: Whack, v. 1. To declare; to give, as a portion of loot.
1955		‘Hal Ellson’ Rock 84: Whack even all round or we tell the cops what you got here.
1979		E. Torres After Hours 66: ‘I know you guys whacked up the swag between you’.
2003		C. Stella Charlie Opera 81: Maybe the hit man who shook him down for an extra fifteen grand was whacking the money with Uncle Anthony.
2005		M.B. ‘Chopper’ Read Chopper 4 140: Come on, Pete. Whack up. [i.e. share a woman sexually].
2010		A. Shand King of Thieves [ebook] ‘And when they got home with the booty, she whacked it up with them, half each’.

2. to charge money; usu. as whack for.

1951		R. Starnes Grant’s Tomb 26: The Umbrella Man, then, was the one who [...] after whacking a percentage, paid off certain policemen.
1961		H.S. Thompson letter 21 July in Proud Highway (1997) 278: I have just whacked Rogue magazine for $350.
1974		G.V. Higgins Cogan’s Trade (1975) 72: You know what that son of a bitch whacked me for Maine? Five hundred a day and expenses.