1. to have an opposite and undesirable result from what was intended
2. to make a loud popping sound due to improper combustion in an engine

1. a loud popping sound made by an engine due to improper combustion
2. an unintended consequence that is opposite to what was desired

Examples

• His plan to embarrass his rival backfired when everyone laughed at him instead.
• The old truck began to backfire as it climbed the steep hill.
• Her attempt to make him jealous backfired completely.
• We heard a loud backfire from the motorcycle.
• The campaign strategy backfired and hurt their reputation.
• The car’s backfire startled the pedestrians.
• Their scheme to frame their competitor backfired spectacularly.