The phrase "keeps secret" refers to the act of concealing information or knowledge from others. However, there are several synonyms that can be used to describe this action. For example, the term "clandestine" implies that the information is hidden in a secretive or covert manner. "Confidential" suggests that the information is intended to be kept private and not shared with others. "Discreet" connotes a sense of caution and carefulness in guarding the information. "Reserved" suggests that the person is deliberately withholding information, while "guarded" implies that they are being protective and cautious. Overall, there are many synonyms for "keeps secret" that convey different shades of meaning and implication.