uggmugg Share definition Flag a person with and ugly mugg, stated as an ugg,ugg cuz they dont deserve the letters "l" and "Y",mainly because they dont got no aliby they're ugly. "why t he fine ones always gotta hang wit 12 or more uggmuggz? uggmugg by troop56 September 19, 2004 0 0 Get merch Get the uggmugg mug. Buy Now — $32.95 See more merch