keep cards close to chest

keep/play your cards close to your chest

to not tell anyone what you plan to do I never know what Martin's next move will be. He plays his cards close to his chest.

Name	Pronounced	Usage
Bowles	[bəulz]
Domitilla	-	Italian, Ancient Roman
Yaromil	-	Medieval Slavic (Hypothetical)
Walker	['wɔ:kə]
Domingo	do-MEENG-go	Spanish
Muhamad	-	Indonesian, Malay