The Collaborative International Dictionary of English v.0.48:
piss off \piss off\, v. t. To anger or strongly annoy; as, his flippant attitude pissed off the teacher. [vulgar] [PJC]The Collaborative International Dictionary of English v.0.48:
piss off \piss off\, v. i. To leave immediately; to scram; -- chiefly British, and sometimes considered vulgar. [Brit., vulgar] [PJC]