Meaning
Back up what you say with concrete action, commitment or resources, especially when words alone are easy. The expression can involve actual money but often refers more broadly to taking responsibility.
Origin
The idiom contrasts two familiar ways of showing commitment: speaking with the mouth and paying with money. Its force comes from the challenge that an opinion or promise is cheap unless the speaker is willing to stake something real on it. The wording belongs to the language of betting, bargaining and practical tests of sincerity; it became especially natural in American English, where a financial stake could stand for proof of conviction. There is no need to imagine a literal coin placed against someone’s lips. Over time, the phrase moved beyond wagers into business, politics, charity and ordinary conversation. A person may be asked to donate, volunteer, invest time or accept a risk rather than merely make impressive claims. Its tone is often challenging, and it can imply that the listener suspects hypocrisy or empty talk.
Examples
You say the local library matters—put your money where your mouth is and volunteer.
The company promised greener operations; now it needs to put its money where its mouth is.
If you believe in the idea, put your money where your mouth is and help fund it.
Frequently asked questions
What does 'Put your money where your mouth is' mean?
Back up what you say with concrete action, commitment or resources, especially when words alone are easy. The expression can involve actual money but often refers more broadly to taking responsibility.