Definition
To maintain secrecy about one's plans or intentions; to not reveal what one is thinking or intending to do.
对（计划等）守口如瓶，对（打算）秘而不宣。
During negotiations, she always keeps her cards close to her chest, making it difficult for the other party to understand her true intentions.
在谈判期间，她总是守口如瓶，让对方难以理解她的真实意图。
He kept his business plans close to his chest until he was ready to make a formal announcement.
他对他的商业计划守口如瓶，直到他准备好正式宣布。
Despite my repeated inquiries, she wouldn't reveal how she planned to handle the issue; she always keeps her cards close to her chest regarding her plans.
尽管我多次询问，她仍不愿透露她计划如何处理这个问题；她对自己的计划总是守口如瓶。