Runt Dick Share definition Flag (Noun)Used mostly as a derogatory slur for a man with small penis. Often used for the smallest "member" in a locker room or boot camp shower. "There goes Pvt. Runt Dick!" "Steve is the teams runt dick freshman this year." Runt Dick by Nubb'n December 17, 2008 0 0 Get merch Get the Runt Dick mug. Buy Now — $32.95 See more merch