backfire

American  

[bak-fahy^uhr] / ˈbækˌfaɪər /

verb (used without object)

backfires, present (3rd person singular) backfired, past participle, past backfiring present participle

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.

   Synonyms:

   bomb, flop, boomerang, miscarry

3. to start a fire deliberately in order to check a forest or prairie fire by creating a barren area in advance of it.

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noun

backfires plural

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.

backfire British  

/ ˌbækˈfaɪə /

verb

1. (of an internal-combustion engine) to emit a loud noise as a result of an explosion in the inlet manifold or exhaust system

2. (of an endeavour, plan, etc) to have an unwanted effect on its perpetrator

   his plans backfired on him

3. to start a controlled fire in order to halt an advancing forest or prairie fire by creating a barren area

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noun

1. 1. an explosion of unburnt gases in the exhaust system

   2. a premature explosion in a cylinder or inlet manifold

2. a controlled fire started to create a barren area that will halt an advancing forest or prairie fire

Other Word Forms

Inflected Forms

Nouns

• backfires
  plural

Participles

• backfiring
  present
• backfired
  past

Conjugated Forms

Present

• backfire
  simple
• backfires
  simple
• have backfired
  perfect
• has backfired
  perfect
• am backfiring
  progressive
• are backfiring
  progressive
• is backfiring
  progressive
• have been backfiring
  perfect progressive
• has been backfiring
  perfect progressive

Past

• backfired
  simple
• had backfired
  perfect
• was backfiring
  progressive
• were backfiring
  progressive
• had been backfiring
  perfect progressive

Future

• will backfire
  simple
• will have backfired
  perfect
• will be backfiring
  progressive
• will have been backfiring
  perfect progressive

Etymology

Origin of backfire

An Americanism dating back to 1775–85; back ² + fire

Explanation

Use the word backfire when you talk about the sound a car makes when a small explosion in its exhaust system pops — sometimes as loudly as a gunshot. Hearing a car's backfire can make you jump, because it makes a sharp, shot-like sound. A backfire is usually caused by unburned fuel, and it can be accompanied by a burst of flame and a brief loss of power in the vehicle, as well as a fairly loud noise. The word comes from an American English term that originally referred to a fire deliberately set to slow the progress of a prairie or forest fire.

Example Sentences

It's nothing new - John Aldridge, Mexico legend Hugo Sanchez and Pele all used the stutter to gain an advantage - but it can backfire spectacularly if the goalkeeper doesn't commit to diving early.

From BBC • Jul. 10, 2026

Gauff drilled her footwork, working to optimize her explosive speed for a slippery surface where hard stops and aggressive sprinting can often backfire.

From Los Angeles Times • Jul. 8, 2026

Wilson, who was the biographer for A. Philip Randolph, the iconic civil rights and labor leader, said the Ohio FBI raids “were an act of desperation that will backfire and only inspire greater voter turnout.”

From Salon • Jun. 16, 2026

But that strategy can backfire in a big way—because customers tend to give lower reviews on weekends than they do during the week.

From The Wall Street Journal • Jun. 12, 2026

This approach is destined to backfire on me, so I decide to dump the rest of my cereal down the drain, too, and talk nonstop on my way to the door.

From "Please Ignore Vera Dietz" by A.S. King

Related Words

• fail
• flop