The phrase grin like a Cheshire cat has become synonymous with Lewis Carroll’s Alice’s Adventures in Wonderland. But while Carroll was no slouch when it came to inventive language, the expression predates his book and was in general use at the time. The enduring success of his comic fantasy helped to popularise the simile.
A decade before Alice was first published (in 1865, by Macmillan), William Makepeace Thackeray used the expression in his novel The Newcomes: ‘That woman grins like a Cheshire cat’, and the OED has an example from a half-century earlier, from satirist John Wolcot in 1812: ‘Lo! like a Cheshire cat our court will grin.’
That the phrase’s origin is unknown has led to some interesting speculation. Martin Gardner, in The Annotated Alice, notes two possibilities: that it derives from grinning lions painted on the signs of inns in Cheshire – where Carroll grew up – or that it comes from a tradition of Cheshire cheeses being moulded into the shape of grinning cats, or marked that way.
Graeme Donald’s Dictionary of Modern Phrase finds the latter hypothesis ‘suspect’ because of the ‘very crumbly texture’ of the cheese in question. He cites Eric Partridge’s suggestion that Cheshire here is ‘a corruption of cheeser’, but doesn’t think cats like cheese enough to make this etymology likely. Donald proposes instead that cat as old slang for prostitute could ‘allude to a girl in a well-patronized Cheshire inn smiling invitingly’. I’m not convinced.
The Cat is one of the best known of Carroll’s characters. When Alice first sees it, lying on the hearth, she asks the Duchess why it’s grinning, and receives the reply: ‘It’s a Cheshire cat […], and that’s why.’ This explains nothing, but it does strengthen the creature’s mystique – which increases when she meets the cat a little later, in the wood, and it answers her questions in gnomic fashion:
‘Would you tell me, please, which way I ought to go from here?’
‘That depends a good deal on where you want to get to,’ said the Cat.
‘I don’t much care where—’ said Alice.
‘Then it doesn’t matter which way you go,’ said the Cat.
‘—so long as I get somewhere,’ Alice added as an explanation.
‘Oh, you’re sure to do that,’ said the Cat, ‘if you only walk long enough.’
The Cat gives Alice directions to the Mad Hatter and the March Hare (‘they’re both mad’, but then ‘we’re all mad here’). In his Annotated Alice, Gardner points out that the phrases mad as a hatter and mad as a March hare (similar to hare-brained) were both current when Carroll was writing, which explains at least partly why he invented these two characters.

Hello! This is a very interesting article for me, as an English teacher, a fan of Alice in wonderland and as a person who was born in Cheshire. Once I gmdid some research in this subject and my final conclusion was that because Cheshire is a big player in the dairy farming industry the children were said to have big white teeth when they smiled because of all the calcium rich products they ate/eat or drink/drank – therefore they called us thing connected with out teeth or smiles. I guess this is one theory of many.
Hello, Jodoe, and thanks for this interesting comment. I like your hypothesis, though I really couldn’t say how likely it is. It seems at least as plausible as one or two of the ideas floated in my discussion, but for now the truth remains elusive.
When one grins — as opposed to smiles (sometimes) — the teeth are always exposed. Exposing teeth is unsettlig/unnerving, because teeth, like claws, are an animal’s natural weapons. The expression ”baring one’s teeth” isn’t really considered a smile, but it COULD pass for a grin.