backfire
🇺🇸
/ˌbækˈfaɪər/
🇬🇧
/ˌbækˈfaɪə(r)/
When a plan or action has a result that is worse than expected, it backfires.
The surprise party I organized for my friend backfired when they found out before the event.
When something makes a loud noise like an explosion, it backfires.
The car's engine backfired, causing everyone to jump.