keep/hold/play your cards close to your chest

hold (one's) cards close to (one's) chest

To keep one's plans, intentions, or information secret from everyone else. Refers to holding one's playing cards close to one's chest in a game, so as not to allow other players to see one's hand. We're all curious about what the boss has been discussing in those meetings with the lawyers, but she's been holding her cards close to her chest. Sorry for not being more straightforward about my plans, but I'm holding my cards close to my chest for the time being.
See also: card, chest, close, hold

keep (one's) cards close to (one's) chest

To keep one's plans, intentions, or information secret from everyone else. Refers to holding one's playing cards close to one's chest in a game, so as not to allow other players to see one's hand. We're all curious about what the boss has been discussing in those meetings with the lawyers, but she's been keeping her cards close to her chest. Sorry for not being more straightforward about my plans, but I'm keeping my cards close to my chest for the time being.
See also: card, chest, close, keep

play (one's) cards close to (one's) chest

To keep one's plans, intentions, or tactics secret from everyone else. Refers to holding one's playing cards close to one's chest in a card game, so as not to allow other players to see one's hand. We're all curious about what the boss has been discussing in those meetings with the lawyers, but she's playing her cards close to her chest. Sorry for not being more straightforward about my plans, but I'm playing my cards close to my chest for the time being.
See also: card, chest, close, play

play your cards close to your chest

mainly BRITISH or

play your cards close to the vest

AMERICAN
If you play your cards close to your chest, you do not tell anyone about your plans or thoughts. Williams is playing his cards close to his chest, especially in terms of his driver line-up for next season. He plays his cards very close to the vest, leaving some attorneys with whom he's worked to describe him as secretive and manipulative. Note: You can also say that someone keeps their cards close to their chest or keeps their cards close to the vest. The Prime Minister was said yesterday to be keeping his cards close to his chest after an informal discussion at cabinet on Thursday. Note: Other nouns are sometimes used instead of cards. Taylor kept his thoughts close to his chest, saying only: `I'm not prepared to comment.' I have no inside information — Dave's playing this one close to his chest. The military's playing this whole operation pretty close to the vest — they generally don't like to talk about future operations. Note: This is a reference to card-players holding their cards close to their chest so that nobody else can see them.
See also: card, chest, close, play

keep (or play) your cards close to your chest (or vest)

be extremely secretive and cautious about something. informal
The previous two idioms both refer to a hand of cards in a card game. If you hold all the cards you have a winning hand, while card players who hold their cards close to their bodies ensure that no opponent can look at them.
See also: card, chest, close, keep

keep/hold/play your cards ˌclose to your ˈchest

not tell others what you are intending to do: He keeps his cards pretty close to his chest. I don’t know whether he plans to buy the house or not. OPPOSITE: show/reveal your hand
See also: card, chest, close, hold, keep, play