backfire

Noun

backfire (plural backfires)

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.

   Synonyms:

   knock, ping

2. An explosion in the exhaust passages of an internal combustion engine.
   • As much of Seattle tries to sleep, the Hellcat supercar goes on the prowl, the howls of its engine and the explosive backfires from its tailpipes echoing off the high-rise towers downtown.2024 May 29, Mike Baker, “Sleepless in Seattle as a Hellcat Roars Through the Streets”, in The New York Times, →ISSN, archived from the original on 06 Jun 2024
3. An explosion in other equipment.
   • The chief causes of rectifier backfiring in the Glasgow units were overheating or unfavourable anode/cathode temperature differential; it has proved possible to overcome these, although occasional backfires do still occur.1962 July, “Failures of multiple-unit electric trains on British Railways”, in Modern Railways, page 53

Verb

IPA/bækˈfaɪə(ɹ)/

backfire (third-person singular simple present backfires, present participle backfiring, simple past and past participle backfired)

1. (intransitive) Of a gun, cannon, Bunsen burner, etc., to fire in the opposite direction, for example due to an obstruction in the barrel.
2. (intransitive) Of a reciprocating engine, to experience a premature ignition of fuel or an ignition of exhaust gases, making a popping sound.
   • It was just after the Biafran war, and all the local people were still jumpy. Any time a car backfired or a police siren howled, they would dive under desks or tables instinctively.1991 February 4, Ayofemi Folayan, “No Sounds Of Silence”, in Gay Community News, volume 18, number 28, page 7
3. (idiomatic, transitive) 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.
   • Her plan backfired on her.
4. To set a back fire (small, controlled fire to limit spread of a larger fire).