—v.i. 1. (of an internal-combustion engine) to have a loud, premature explosion in the intake manifold.
2. to bring a result opposite to that which was planned or expected: The plot backfired. 3. to start a fire deliberately in order to check a forest or prairie fire by creating a barren area in advance of it.
—n. 1. (in an internal-combustion engine) premature ignition of fuel in the intake manifold.
2. an explosion coming out of the breech of a firearm.
3. a fire started intentionally to check the advance of a forest or prairie fire.