SELL OUT

v. 1a. To sell all of a certain thing which a store has in stock. In the store's January white sale the sheets and pillowcases were sold out in two days. 1b. To sell all the stock and close the store; go out of business. The local hardware store sold out last month and was replaced by a cafe. 2. informal To be unfaithful to your country for money or other reward; be disloyal; sell a secret; accept a bribe. In the Revolutionary War, Benedict Arnold sold out to the British. The dishonest wrestler sold out to his opponent for a hundred dollars.