The idiom "steal someone's thunder" means to take credit for someone else's idea or to use someone else's idea for your own benefit. It can also mean to do something that takes attention away from someone else's achievement or success.
The origin of this idiom comes from a play by John Dennis in 1709. In the play, there was a sound effect of thunder that Dennis had created, but another play used the same sound effect before Dennis could use it in his own play. This made Dennis angry and he said that the other play had "stolen his thunder."
You can use this idiom in different situations. For example, if someone comes up with a good idea at work and you present it as your own, you are stealing their thunder. Or, if someone is about to announce some good news and you announce your own good news first, you are stealing their thunder.
In general, it is not a good thing to steal someone's thunder because it is unfair and can damage relationships. It is important to give credit where credit is due and to let others have their moment to shine.
• The famous author was frustrated when a newcomer to the literary scene stole her thunder by releasing a book that received more critical acclaim.
• I didn't want to steal my friend's thunder, so I waited for her to tell everyone about her new job first.
• The politician was furious when his rival stole his thunder by announcing the same policy he had been working on for months.
• My little brother always tries to steal my thunder by doing the same things I do.
• The CEO announced the new company policy before the manager had a chance to do so, stealing his thunder.
• Despite his impressive performance, the new employee's success was overshadowed by his colleague who stole his thunder with a presentation that blew everyone away.