This
database is a comprehensive collection of all the American idioms and slang available.
American Idioms are many and varied. We hope you enjoy our collection. We are adding more all the time.
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have something that you can use to gain an advantage (in a card game the ace is often the most valuable card and a cheater could have an ace up his or her sleeve to use against an opponent)
I have an ace up my sleeve which should help me when I meet my boss tomorrow.
to preserve one`s good reputation or dignity when something has happened to hurt it
Our boss was very embarrassed when our company lost a lot of money. However, he was able to save face when he showed that the problems were outside of his control.