lily ass Share definition Flag a white, especially a rich white teenage boy who tries to pretend to be black "Dude, you live in a mansion in Westchester and you drive one of your dad's beamers to school. Stop trying to act like a gangsta. What a lily ass." lily ass by crazyhorseva May 2, 2004 0 0 Get merch Get the lily ass mug. Buy Now — $32.95 See more merch