Green’s Dictionary of Slang

(N.Z. prison) either ‘All Crims Are Cool’ or ‘All Cops Are Cunts’; esp. as a tattoo.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 5/1: ACAC abbr. standing for an expression, 'All Crims Are Cool' and 'All Cops Are Cunts'. [similar to the current British prison expression, ACAB 'All Coppers Are Bastards'. ACAC appears frequently as a tattoo, identifying the wearer as an older criminal.