Short and silly term for Mother Fu(k#r. It first started as Muf or Muv and was soon misunderstood by silly old white dude's. Then their son's friends started saying it as a joke to make fun of the "old man". Soon it became a normal slang to emphasize almost any sentance.
"It's hotta den a MUG up in her!"
by Kizzurt June 02, 2005