v.1. To wager something on the outcome of some event: I gambled all my money on the first race. They don't like to gamble on poker games; they just play for fun.
2. To wager something on some participant in an event: I gambled $50 on my favorite horse.
3. To anticipate or foresee something: I didn't gamble on it raining, so I hadn't brought an umbrella.