“Steal someone’s thunder” has a wonderfully literal origin. It is usually traced to the English playwright John Dennis, who created a new method for making thunder sounds in the theater in 1709. His play did not succeed, but another theater company reportedly used his thunder effect anyway.
According to the famous story, Dennis complained, “They will not let my play run, but they steal my thunder!” That complaint is where the idiom comes from. At first, it referred quite directly to taking someone else’s idea or stage effect. Over time, the meaning widened.
Today, the phrase usually means taking attention, praise, or impact away from someone else, especially at the wrong moment.
- Taking attention: Announcing your promotion at your friend’s party can steal their thunder.
- Taking credit: Presenting a coworker’s idea as your own can steal their thunder.
- Ruining a reveal: Sharing the ending of someone’s story before they tell it can steal their thunder.
So the idiom started with actual thunder, but now it is used for any moment when one person unfairly takes the spotlight from another.