1.
If someone or something pisses you off, they annoy you. (INFORMAL, RUDE)
It pisses me off when they start moaning about going to war.
PHRASAL VERB: V n P
pissed off
I was really pissed off.
ADJ
2.
If someone tells a person to ~, they are telling the person in a rude way to go away. (BRIT INFORMAL, RUDE)
PHRASAL VERB: V P