Originally Posted by Ayla_SquareTurtle

Backfire n.

1. An explosion of prematurely ignited fuel or of unburned exhaust gases in an internal-combustion engine.
2. The backward escape of gases or cartridge fragments when a gun is fired.
3. A fire started in the path of an oncoming fire in order to deprive it of fuel and thereby control or extinguish it.

intr.v., -fired, -fir·ing, -fires.

1. To explode in the manner of or make the sound of a backfire.
2. To start or use a backfire in extinguishing or controlling a forest fire.
3. To produce an unexpected, undesired result.