steal sb's thunder
to do what someone else was going to do before they do it, especially if this takes success or praise away from them:
Sandy stole my thunder when she announced that she was pregnant two days before I'd planned to tell people about my pregnancy.

[TahlilGaran] Advanced Learner's Dictionary ▲

steal thunder
steal (someone's) thunder
to do something that takes attention away from what someone else has done.
I kept quiet about my pregnancy because Cathy was getting married, and I didn't want to steal her thunder.

[TahlilGaran] English Idioms Dictionary ▲

steal thunder
to do or say something that another person had planned to do or say
My colleague stole my thunder when he announced that he was leaving the company before me.

[TahlilGaran] English Idioms Dictionary ▲

steal someone's thunder
steal (someone's) thunder
to do something that takes attention away from what someone else has done.
I kept quiet about my pregnancy because Cathy was getting married, and I didn't want to steal her thunder.

[TahlilGaran] English Idioms Dictionary ▲

steal someone's thunder
to do or say something that another person had planned to do or say
My colleague stole my thunder when he announced that he was leaving the company before me.

[TahlilGaran] English Idioms Dictionary ▲

steal one's thunder
v. phr. To do or say something, intentionally or not, that another person has planned to say or do.
Fred intended to nominate Bill for president, but John got up first and stole Fred's thunder.
Mary was going to sing "Oh! Susanna," but Ellen did it first and Mary said Ellen had stolen her thunder.
Smith heard that Jones was going to offer a new law which people wanted, so he himself proposed the law first, stealing Jones' thunder.

[TahlilGaran] English Idioms Dictionary ▲