To make one's plans, intentions, ideas, or resources known to others, especially those that were previously hidden or kept secret. (Also expressed as "reveal (one's) hand"; both phrases refer to displaying one's cards ("hand") during a card game.) In business negotiations, it's important that you don't reveal your cards right away, or you might risk losing out on the best deal possible. Pressure from the government is forcing the notoriously secretive CEO to reveal his cards regarding his company's tax profile and offshore accounts.