The phrase "card up one's sleeve" means to have a hidden advantage or secret tactic that can be used to gain an advantage. Synonyms for this phrase include "ace in the hole," "secret weapon," "trump card," "hidden strength," "hidden resource," and "surprise tactic." These words are often used in strategic planning, negotiations, and competitive scenarios where one needs to have an advantage over others. Having a card up one's sleeve can give an individual a sense of confidence and control as they navigate through challenges and opportunities. It is always wise to have a few tricks up one's sleeve, just in case they are needed.
