Green’s Dictionary of Slang

(orig. US milit.) an innocent, a novice.

1935		E. Freeman ‘The Whirling Hub’ in Afro-American 8 June 18/2: The Fuller Brush Man is trying to learn why Gene Vanderpool won’t quit and give the F.N.G. a break.
1966		N.Y. Times Mag. 30 Oct. 104: F.N.G. designates a ‘foolish new guy’.
1967		E. Shepard Doom Pussy 217: Major Nails says several FNGs* believe it. [footnote] *Fucking new guys.
1972		T. O’Brien If I Die in a Combat Zone (1980) 74: Wolf said, ‘Look, F.N.G., I don’t want to scare you.’.
1985		(con. 1969–70) D. Bodey F.N.G. (1988) 28: I don’t know who I am. I am the F.N.G.
1993		T. Jones Pugilist at Rest 12: I was fresh meat, F.N.G. – a Fucking New Guy.
2002		J. Lerner You Got Nothing Coming 260: Some skinheaded FNG (‘fucking new guy’) is pumping iron behind the Wood pile’s gated community.
2008		Simon & Burns ‘Get Some’ Generation Kill ep. 1 [TV script] ‘Look at this motherfucker.’ ‘FNG, Sarge’.