Throw a wrench in the works.
Disrupt a plan.
To "throw a wrench in the works" is to create a sudden obstacle that prevents something from going as planned. Picture a literal wrench thrown into machinery, grinding it to a halt—the chaos it causes mimics the disruption caused in one's plans.
Example Sentences
His sudden resignation really threw a wrench in the works.
His sudden resignation disrupted everything.
Just when we thought the project was on track, the software glitch threw a wrench in the works.
The software glitch disrupted the project just when we thought it was on track.
The unexpected weather threw a wrench in the works, delaying the construction schedule by a week.
The unexpected weather disrupted the construction schedule, causing delays.
