ass stain Share definition Flag Someone who is a skid mark on society, dumb and incoherent. Usually when drunk does the real perpetrator of this crime come out. Nate, " Man was kolt fucked up tonight." Mike " Yeah he was acting like a real ass stain." ass stain by timmy johnston April 7, 2007 0 0 Get merch Get the ass stain mug. Buy Now — $32.95 See more merch