[{"Bold_text": "verb (used without object)", "List Items": ["(of an internal-combustion engine) to have a loud, premature explosion in the intake manifold.", "to bring a result opposite to that which was planned or expected:The plot backfired.Synonyms: bomb , flop , boomerang , miscarry", "to start a fire in order to check a forest or prairie fire creating a barren area in advance of it."]}, {"Bold_text": "noun", "List Items": ["(in an internal-combustion engine) premature ignition of fuel in the intake manifold.", "an explosion coming out of the breech of a firearm.", "a fire intentionally to check the advance of a forest or prairie fire ."]}]