Origin:
The idiom is thought to have originated from card games, where a skilled player might keep a winning card hidden, ready to play at the right moment. The "ace" in this context refers to the highest card in many card games, making it a powerful asset.
Example:
* "The negotiators went into the meeting thinking they had a strong position, but the other side had an ace up their sleeve – a secret offer from a rival company."
* "Don't be fooled by their seemingly simple strategy. They always have an ace up their sleeve."
Similar idioms:
* Up one's sleeve: This is a shortened version of the idiom, conveying the same meaning.
* Have a trick up one's sleeve: This emphasizes the deceptive or cunning aspect of the hidden advantage.
* Hidden weapon: This is a more direct way of saying the same thing, focusing on the power of the concealed advantage.