Green’s Dictionary of Slang

n.f.g. phr.

[abbr.]

(US) no fucking good.

[US]E. Torres Q&A 131: With all due respect, he’s a shtonk [...] N.F.G., with the oak leaf clusters. Cold man.
[US]Alt. Eng. Dict. 🌐 N.F.G. (acronym) No Fucking Good. Usage example: Your idea is NFG.