Green’s Dictionary of Slang

1. (US) to make a contribution, a donation; to hand over.

1890		E. Field ‘The Conversazzhyony’ Little Bk of Western Verse 152: For her sake, he’d whack up every cussid cent he’d got!
1894		Mirror of Life 26 May 14/2: He abuses [...] a poor man because he is poor, and a rich man because he does not ‘whack up’ .
1902		Guilelmensian (Williams Coll.) 289: Learned to Doctor his Cash Account [...] in order to Whack up the Long Green to Ally.
1909		G.R. Bacchus Maudie 117: ‘It’s going to be £250 apiece [...] you may as well whack up now’.
1910		Sun. Times (Perth) 19 June 2nd sect. 10/2: No less than 24,000 dollars were taken at the doors when Stanley Ketchel and Sam Langford fought their six-rounds go [...] Nearly £1000 per round — or £333 6s. 8d. per minute — whacked up.
1973		J. McNeil The Chocolate Frog and The Old Familiar Juice 115: whack up, to share.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 202/1: whack up v. to hand over property or contraband (usu. on demand).

2. to come up with, to create.

1899		A. Binstead Houndsditch Day by Day 55: A fund of a few guineas was soon whacked up.
1923		Wodehouse Inimitable Jeeves 52: Worships the ground you tread on, but can’t whack up the ginger to tell you so.
1952		T.A.G. Hungerford Ridge and River (1966) 75: I’ll send young Albie over – he can show you how to whack up a leafie.
1961		B. Crump Hang On a Minute, Mate (1963) 51: I’ll whack up a loaf that your mother’d be proud of.
1978		R. Price Ladies’ Man (1985) 143: By six I was whacking up a salad in the kitchen.

3. (US) to acquire money, esp. by bribery.

1981

H. Gould Fort Apache, The Bronx 14: You know what those guys are whackin’ up every month? [...] These guys are getting three or four thousand a month from the numbers people alone.