1. A masculine face
2. A face that looks like a man.
This term refers to the masculine face of a non-passing trans woman. Middle age APG huns are notorious for having a man-mug. Usually accompanied by a cheap looking wig and clown like make up.
Fuck, I hate my man-mug so much. I gotta get that facial feminization surgery to fix that shit.
Yuck! That hun's man-mug is giving me a bad case of 2nd hand dysphoria.