1. rude slang To greatly anger or irritate someone. I think I might start cycling to work in the morning—this traffic really pisses me off! I think I pissed off Janet with my comment earlier.

2. rude slang To depart from somewhere quickly or abruptly. Often used as an imperative. Why don't you just piss off if you're not going to help us? I didn't know anyone at the party, so I pissed off around 11.