to steal or take something from someone
boy: girl i know you didn't just faness my shades?
girl: they clearly in my hand aint they?
guy1: aye bruh i just fanessed this iPhone from the teacher!
guy2: lehh go!! i would sell that shit for $300!!!
Used when some has 'pretty boy swag.' Usually when your giving your boy props on his outfit. The opposite is also used, 'no faness'.
Kid: "Oh booy, that jacket got faness on the real doe."
Mike: "Thanks bruh"
Kid:"HAHA!NO FANESS,NO FANESS BOOOY, NO FANESS"
Mike: Yo this jacket got faness till' death whatchu talkin bout?
Kid:"HAHAHA take that shit off boy you look like Bill Cosby.