The definition of pissed is a vulgar term that is very angry or annoyed.(adjective)
When your wife has an affair with your best friend, this is an example of a time when you are pissed.
Pissed is a vulgar term that means you have urinated.(verb)
When you went to the bathroom and urinated, this is an example of a time when you pissed.
See pissed in Webster's New World College Dictionary
See pissed in American Heritage Dictionary 4