Uni-Baller Share definition Flag A man and/or boy who gets their testicle knocked out usually by a girl. So the person only has one testicle. John Ed got his left nut knocked out by Anniela during Lunch, now he takes the title as Uni-Baller. Uni-Baller by civic June 2, 2005 0 0 Get merch Get the Uni-Baller mug. Buy Now — $32.95 See more merch