grin like a Cheshire cat

Idioms  

1. Smile broadly, especially in a self-satisfied way. For example, John ended the set with a beautiful serve, an ace, and couldn't help grinning like a Cheshire cat. The ultimate origin of this expression, appearing in print since the late 1700s, is disputed, but its most famous exponent was Lewis Carroll, in whose Alice's Adventures in Wonderland the grinning cat gradually vanished from view, with its grin the last part to vanish.

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Example Sentences

When the conversation is flowing effortlessly about a niche show you both like, you can’t help but grin like a Cheshire cat.

From Los Angeles Times • Dec. 6, 2023

That some of this cheerfulness may be simply animal is true, and that a man may be a dullard and yet sit and "grin like a Cheshire cat;" but we are not speaking of grinning.

From Brave Men and Women Their Struggles, Failures, And Triumphs by Fuller, O. E. (Osgood Eaton)

Shine 'em till they grin like a Cheshire cat eatin' cheese!

From Stephen Archer and Other Tales by MacDonald, George

"You grin like a Cheshire cat," she remarked.

From The Treasure of Heaven A Romance of Riches by Corelli, Marie

The English-born air ace greeted him with a grin like a Cheshire cat.

From Dave Dawson at Casablanca by Bowen, Robert Sydney