Green’s Dictionary of Slang

pretending to be more experienced than one actually is.

1992–2003		P. Atoon Rap Dict. 🌐 shife (adj) See mark or newjack. A rookie or one who purports to be more than he is. ‘And he knew he was shife, he knew he was hype’ -- Bust Down (Nasty bitch (intro) [1993]).
1995		‘K-Rino’ ‘Two Roads’ 🎵 on Danger Zone [album] He started makin bank, putting freaks, and high cappin / He got to acting shife and people’s dope he started taking / Now he’s in the grave cuz he crossed that Jamaican.