1. An adjective to describe a person with mug-like features, or who has just done something which is clearly stupid.
"Oi, you, stop impersonating an ambulance. This is a Church. You Mugface."
by Dave Kaboshi June 04, 2007
Comically ugly, Unfortunate in appearance, One which should generally be avoided.
You're a right mugface
by Miss GRP February 09, 2008