backfire

Meanings

1. A premature explosion in the cylinder of a gas or oil engine during the exhaust or the compression stroke, tending to drive the piston in the wrong direction.
2. An explosion in the exhaust passages of an internal combustion engine.
3. An explosion in other equipment.
4. Alternative form of back fire.

1. Of a gun, cannon, Bunsen burner, etc., to fire in the opposite direction, for example due to an obstruction in the barrel.
2. Of a reciprocating engine, to experience a premature ignition of fuel or an ignition of exhaust gases, making a popping sound.
3. To fail in a manner that brings down further misfortune.
4. To set a back fire (small, controlled fire to limit spread of a larger fire).

Etymology

From back + fire.