keep something a secret
صداشو در نیار، به کسی نگو، بین خودمون باشه
We are going to have a surprise birthday party for Maria, keep it under your hat and don’t let anyone know about it.
keep something under your hatinformal to keep something secret
keep (something) under one’s hat
to keep (something) secret
Keep it under your hat but I’m getting married next week.
keep sth under your hat
If you tell someone to keep a piece of information under their hat, you are asking them not to tell anyone else about it.
Look, if I tell you something, will you promise to keep it under your hat?
He kept it all very much under his hat.
keep (something) under one's hat
Definition of keep (something) under one's hat
: to keep (something) secret : to not tell anyone about (something)I'll tell you what happened, but you have to keep it under your hat.