backfire v. [ I ]
①（引擎）发生回火。
=(of an engine) to make a loud noise as a result of fuel burning too early

②（计划）产生适得其反的结果。
=(of a plan) to have the opposite result from the one you intended

【例句】
I was woken by the sound of a truck backfiring.
卡车引擎的回火声把我惊醒了。

Her plans to make him jealous backfired on her when he started dating her best friend.
她原本想让他妒嫉，没想到最后他却和她最好的朋友好上了。