A gamble is a risky action or decision that you take in the hope of gaining money, success, or an advantage over other people.

If you gamble on something, you take a risky action or decision in the hope of gaining money, success, or an advantage over other people.

If you gamble an amount of money, you bet it in a game such as cards or on the result of a race or competition. People who gamble usually do it frequently.