Green’s Dictionary of Slang

not worth a good goddam phr.

also not worth a good God-damn, ....good gosh-damn

(US) absolutely worthless; thus occas. antonym worth a good goddam, worthwhile, valuable (see cit. 1930); see also under worth a... phr.

[US] ‘I Don’t Want Any More France’ in J.J. Niles Singing Soldiers (1927) 71: Gave myself to Uncle Sam, / Now I’m not worth a good God damn.
[US]E. Caldwell Bastard (1963) 32: Flo ain’t worth a good God-damn!
[US]R. Whitfield Green Ice (1988) 155: Hell! [...] Never had a tip yet worth a good goddam.
[US](con. 1944) N. Mailer Naked and Dead 439: Ah ain’t worth a good goddam.
[US]J. Thompson Pop. 1280 in Four Novels (1983) 368: It don’t make a good gosh-damn about anything.