keep something quiet
US /kiːp ˈsʌmθɪŋ ˈkwaɪət/
UK /kiːp ˈsʌmθɪŋ ˈkwaɪət/

1.
to keep something secret or not tell anyone about it
:
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Can you keep this quiet for a while?
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We need to keep this quiet until the official announcement.
to keep something secret or not tell anyone about it