Plays close vest is an idiomatic expression that means someone is being secretive or not revealing everything they know. There are many synonyms for this phrase, such as keeping secrets, being tight-lipped, being guarded, and being discreet. Other synonyms may include being cautious, being circumspect, being reticent, being reserved, and being uncommunicative. These phrases all describe someone who is not willing to reveal their thoughts or actions to others, whether out of fear, privacy, or a desire to keep certain information to themselves. It is important to choose the right synonym based on the context, tone, and purpose of the sentence being used.