The phrase "be cards" can be replaced with several synonyms depending on the context of the sentence. For example, if the phrase is used to mean "be honest" or "be straightforward", similar phrases that could be used include "be truthful", "be frank", "be candid", or "be forthright". If the phrase is used to mean "be in control", synonyms such as "be the boss", "be the leader", or "be in charge" could be used. On the other hand, if "be cards" is being used in a playing card context, synonyms could include "play cards", "deal cards", or "shuffle cards". Choosing the right synonym can help make your communication more clear and effective.