/pis/ , n. , v. pissed, pissing . Vulgar.
n.
1. urine.
2. take a piss , to urinate.
v.i.
3. to urinate.
4. piss away , Slang. to squander; fritter away:
5. piss off , Slang.
a. to anger.
b. to go away; leave (often used imperatively).
[ 1250-1300; ME pissen pissier pisiare (imit.) ]