steal (someone's) thunder

Translations
украсть (чью-то) славу
She didn't want to announce her promotion at the party because she didn't want to steal her friend's thunder.
Она не хотела объявлять о своем повышении на вечеринке, потому что не хотела украсть славу своей подруги.
Definitions
To take credit for someone else's idea or to preemptively use their idea or advantage, often in a way that diminishes their impact or recognition.
Words
steal

verb
украсть
someone

pronoun
кто-либо
s
чей-то
thunder

noun
гром