Definition of plug-ugly in US English:

plug-ugly

noun

North American
informal
  • A thug or villain.

    • ‘A broad plug-ugly was trying to twist around, shaking and shimmying his forearm caught by her hands.’
    • ‘Two huge plug-uglies stood on either side of the door, arms folded.’
    • ‘The filmmakers' desire to create an unstuffy, modern version of the Renaissance monarch merely turns him into a boorish, violent plug-ugly.’

adjective

North American
informal
  • Very ugly.

    ‘that was one plug-ugly dress’
    • ‘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.’
    • ‘But the belt clip is plug-ugly and poorly designed and oversized - what happened, it seems to have been made and fitted by a different company?’
    • ‘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?’

Origin

By association with the verb plug in the informal sense ‘hit with the fist’.

Pronunciation

plug-ugly

/ˈpləɡ ˈəɡli//ˈpləɡ ˈəɡlē/