F-Star Share definition Flag (v.) (trans.) To give someone the finger and then immediately show that person your butthole. "Hey Mike, whay do you look so sick?" "Dude, a bum just gave me the F-Star, and it was GROSS!!" F-Star by F-Tastic March 7, 2013 0 0 Get merch Get the F-Star mug. Buy Now — $32.95 See more merch