- (Internet) Initialism of chill the fuck out.
2006, Joe F. "rb608", “OT: CTFO Rant”, in rec.outdoors.fishing.fly, Usenet:
- Personally, I don't much give a shit how much some of you may dislike some others, but sweet baby jesus, Chill The Fuck Out, would ya? ... If ya gotta do it, do it; but CTFO a little, eh?