An awkward, scratchy sound from deep within the throat, that is widely used in VT to describe ugly, nasty, vulgar, stupid bitches; it can also be used as a noun.
Ewww... look at that nasty BOAHH!
BIG DAN: "BOAHH!"
LIL' AL: (looking all around him)"Where!?! Where!?!"
Nasty! Do you see that fugly bitch? BOAHH!