Source : WordNet®

backfire
     n 1: a loud noise made by the explosion of fuel in the manifold
          or exhaust of an internal combustion engine
     2: a miscalculation that recoils on its maker [syn: {boomerang}]
     v 1: have an unexpected and undesired effect; "Your comments may
          backfire and cause you a lot of trouble" [syn: {backlash}]
     2: emit a loud noise as a result of undergoing a backfire; "My
        old car backfires all the time"
     3: set a controlled fire to halt an advancing forest to prairie
        fire