a party for a man who is going to get married, to which only his male friends are invited.
On Keith's stag night, his friends left him tied to a lamp-post in Trafalgar Square, wearing only his underpants.
(redirected from a stag night)
stag night
A groom's outing with his male friends before his wedding; a bachelor party. Mark knew that his stag night had gotten out of control when the police arrived.