(of a gun, cannon, Bunsen burner, etc.) To fire in the opposite direction, for example due to an obstruction in the barrel.
(of an engine) To experience a premature ignition of fuel or an ignition of exhaust gases, making a popping sound.
To fail in a manner that brings down further misfortune.
His attempt to make money by importing luxury cars backfired horribly when fuel prices tripled.
A failure that leads to further misfortune.