Green’s Dictionary of Slang

(US) an unsophisticated person (in criminal terms), a blunderer, one who makes a mess, lit. and fig.

1960		(con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 23: Cacker – a white-collar worker.
1997–2002		Alt. Eng. Dict. 🌐 cacker someone who cacks Used as provocative gesture to unsavoury characters: eg ‘Sod off you cacker Rawhide’.