When someone is so stupid they think they are fire proof
Person 1: how did he burn himself
Person 2: he is fire retarded
When you intentionally set out to make a fire with bad intentions, but the fire never happens.
Person 1: I put my campfire right next to my pile of highly combustible twigs.
Person 2: Did you start a wildfire?
Person 1: No, I'm fire retarded.