Hold/keep/play your cards close to your chest
Definition 1 of 1
Pro Tip 1/3Secretive Strategy
Indicates keeping strategies or plans secret to gain advantage or avoid showing weaknesses. 
Negotiating for a raise, she played her cards close to her chest, revealing little about her other job offers.
Pro Tip 2/3Cautious Sharing
Suggests being careful with what information you share to prevent giving others an advantage. 
In the game of diplomacy, the ambassador held his cards close to his chest, not giving away his country's intentions.
Pro Tip 3/3Competitive Contexts
Commonly used in situations involving competition, like business, sports, or games. 
The poker player kept his cards close to his chest, making it hard for opponents to guess his hand.