Literally a public urinal in most major European cities, but sometimes a creative way of saying you are pissed off, or pissed off at someone, or someone is an idiot; sometimes used as an exclamation.
Damn it, Nelson, you are a real pissoir!

PISSOIR! I spilled the cleaning fluid on the shelf!
by Fast Bobby April 12, 2004
Get the pissoir mug.