Green’s Dictionary of Slang

(US) new, uninitiated, novice.

1985		(con. 1969–70) D. Bodey F.N.G. (1988) 102: That newby fuckin’ El-tee best watch his shit.
2012		C. Eble (ed.) UNC-CH Campus Sl. 2011 8: NOOB — inexperienced, lacking knowledge; stupid.