1. to have a secret or surprise plan or solution (to a problem); a powerful and often secret weapon, advantage, etc., that can be used if it is needed

1. I don’t know how Henry is going to get his mom to buy him a bike, but I’m sure he has an ace up his sleeve.

2. They still have some surprises up their sleeves.

3. It looks like Joanne is going to lose, but I wouldn’t be too sure. She may have an ace up her sleeve.

4. No matter how many times I think Paul might lose to me in a game of chess, he never does. He always has an ace up his sleeve and wins every game.

5. If the electricity goes out during the birthday party, don’t worry. I’ve got something up my sleeve.

6. The coach always keeps a few tricks up his sleeve.