It's rude and vulgar so please don't ever use it if you can :) It's like: go away and leave me alone but in a more impolite and uneducated way. You should not use it in any written work - that's for sure :)

It's a rude way to tell someone to go away from you, or to mind their own business.

Also: "John is pissed off" (annoyed/upset) or for provocation: "don't piss off John, he's in a bad mood today."

Hi, It means the same as 'f*** off'. Go away, I really don't want you to be near me right now. Usually said when the speaker is very angry. Hope that helps :)

it like "feeling annoyed"