- have an ace upone's sleeve
- have something up one's sleeve & have an ace upone's sleeveFig. to have a secret or surprise plan or solution (to a problem). (Alludes to cheating at cards by having a card hidden in one's sleeve.) •
I've got something up my sleeve, and it should solve all your problems. I'll tell you what it is after I'm elected.
•The manager has an ace up her sleeve. She'll surprise us with it later.
Dictionary of American idioms. 2013.