Unintentional Bad Ass Share definition Flag Unintentionally doing something that would normally be considered badass. Dan left school after 5th period because he thought he was done with school, he gets off after 6th on days like today. He's an Unintentional Bad Ass. Unintentional Bad Ass by dfein6 January 21, 2010 Get the Unintentional Bad Ass mug.