Fyfo is an acroynm for Fuck ya face off. Commonly used in utter disapproval, hate rage, or just to be a dick. Replaces the old saying, "Wipe that smirk off your face."
Dude1: You think that's funny? Wipe that smirk off your face!!!
Guy2: Fyfo fuck ya face off first.
(fife-oh) n. A woman who is attractive from afar but once seen up close is quite the opposite. (F)ifty-(Y)ard (F)ake (O)ut.
Etymology: A football move from 50 yards away which causes a player on the opposing team to commit toward the wrong side of the field.
It was a good thing my bus sloshed mud onto that fyfo because I was considering making contact with her.