Definition of to flip off in English English dictionary
To make a rude or obscene gesture (at somebody). (The specific rude and offensive gestures vary between countries.)
He was so pissed he flipped off the policeman.
(deyim) When you make a fist and extend your middle finger with the back of your hand pointing toward the person you intend it for. A sort of "fuck you" gesture. Also known as "giving the finger"