plug-ugly 
informal, chiefly North American
noun (plural plug-uglies)
A thug or villain.Two huge plug-uglies stood on either side of the door, arms folded....
- A broad plug-ugly was trying to twist around, shaking and shimmying his forearm caught by her hands.
- The filmmakers' desire to create an unstuffy, modern version of the Renaissance monarch merely turns him into a boorish, violent plug-ugly.
adjective
(Of a person) very ugly.He has gone off for good with that plug-ugly researcher....
- Okay, so you are not plug-ugly and you don't find it impossible to lure women into your dizzying orbit, but just what is it about you that turns out to be so utterly repellent?
- Gone were her cauliflower ears, gone was her pug nose, her squat face had ballooned out, her once squinty eyes were now just slits in her plug-ugly face.
Origin
By association with the verb plug in the informal sense 'hit with the fist'.