Slit-nick

(Basically real son of a bitch, worse than a motherfucker; might as well be racist against any race... it's an insult of the highest value. If your worst enemy wanted to insult you they would think twice to use the term slit-nick, that's how insulting it is. You don't want to ever be called a slit-nick, by anybody, ever.

"You slit-nick son of a bitch"