Green’s Dictionary of Slang

1. (also becack) to defecate; also in fig. use.

1436		‘Libel of Eng. Policy’ in Wright Political Poems (1859) II 170: Wythoute Calise in ther buttere the cakked.
1596		‘Misdiaboles’ Ulysses upon Ajax 66: A lubber to cry, Mother go cack, when he is able to truss himself, is indecent.
1605		Marston Dutch Curtezan II i: My wit has no edge, and I may goe cacke in my pewter.
1656		Mennis & Smith et al. ‘A Song’ Wit and Drollery 92: The hole was beshit that she could not sit, but did cack as she lay on her side.
1658		Mennis & Smith ‘Ad Johannuelem Leporem’ Wit Restor’d (1817) 155: Philip [...] Made such a thrust at Phoebe, with his Club, That made the Parthians cry, she will becack us.
1672		J. Phillips Maronides (1678) V 67: At this same play makes others cack.
1683		London Jilt pt 2 102: A Chamber-Pot, wherein I had cacked seven or eight times [...] to purge my Body.
1728		Supplement to the Profund 15: Some Play, some Eat, some Cack aganst the Wall.
1792		‘There Was Twa Wives’ Burns Merry Muses of Caledonia (1965) 70: The beans and pease cam down her thighs, / And she cackit a’ her stockins.
1890		‘Neaniskos’ Priapeia Ep. lxx 69: Glance at my nature, Thief! and estimate The mentule thou must cack and what’s its weight.
1937–84		Partridge DSUE (1984) 172/1: late C.19–20.
2001		G. Pelecanos Right As Rain 264: Somethin’ had cacked down here, that was for certain [...] She knew that smell.
2006		D. Mitchell Black Swan Green 114: Looked like you cacked yer cacks!
2018		C. Hammer Scrublands [ebook] ‘Funniest thing you ever saw. He was ranting on about killing the priest. Allen and me were cacking ourselves’.
2023		R. Milward Man-Eating Typewriter 75: I wasn’t sure if the toff-classes even cacked or piddled .

2. (also kack it) in fig. use, to be terrified.

1966		(con. 1954) J. McGrath Events While Guarding the Bofors Gun I iii: You’re sitting there cacking yourself because you thought I was a bloody Orderly Officer, aren’t you?
2000		P. Howard Miseducation of Ross O’Carroll-Kelly (2004) 147: I am totally kacking it [...] We’re all, like, so nervous.
2004		(con. 1988) N. ‘Razor’ Smith A Few Kind Words and a Loaded Gun 314: This was probably the first time this besuited prick had ever spoken to prisoners, and he was cacking himself.
2005		P. Howard Curious Incident of the Dog in the Nightdress 37: I’m suddenly kacking it, the old hort doing ninety to the dozen.

3. (Aus.) in fig. use, to be convulsed with laughter.

1987		Sydney Morn. Herald Guide 22 May 13/1: On the other hand, these are also the kind of people who don't cack themselves when they see someone slip on dog poo or when someone else (preferably a distinguished type) farts dreadfully in public.
1990		T. Winton Human Torpedo 132: They went back to their bikes, sweating and breathless and cacking themselves laughing.
1995		Canberra Times 28 July 16/2: My divot usually went further than the ball and I could tell by the onlookers’ carefully composed blank faces that they were actually cacking themselves inside with laughter.
2002		J.A. Mawter So Feral! 133: By this time I’m cacking myself. I laugh so much I want to wee.
2012		Sydney Morn. Herald Spectrum 28 Jan. 32/1: Go rent a film that feigns to be cool for its day, such as Puberty Blues from 1981, and you’ll cack yourself to the max, dude.