1. Yeah right, whatever, sure. (sarcastic)
2. Get lost, go away, fuck off.
3. To get someone mad.
1. "Yeah I dumped 20 pills of ecstacy last night."
"Piss off cunt."
2. "You'd better piss off outta here before the cops arrive."
3. "You've gone and pissed off the IRS?Yo' in sum shit."