Idiom
Don't judge a book by its cover
Don't judge a book by its cover means you should not form an opinion of someone or something based only on how it looks.
How people use it
People say it when appearances turn out to be misleading: the restaurant looked shabby, but the food was amazing, so don't judge a book by its cover. It applies to people, places, products and ideas. Common forms are don't judge a book by its cover and you can't judge a book by its cover. It is a proverb, often used to teach or gently correct someone. The tone is neutral and friendly.
Also said: you can't judge a book by its cover.
Examples
- The little roadside shack served the best tacos in town, so don't judge a book by its cover.
- You can't judge a book by its cover; the quiet new student turned out to be hilarious.
- My grandmother taught me not to judge a book by its cover when meeting new people.
Where it comes from
Sayings that warn against trusting appearances are ancient. The book version appears in American English by the 1920s, in forms such as "you can't judge a book by its binding", and it spread widely in the decades after that.
Check yourself
1. What is the lesson of "don't judge a book by its cover"?
Answer: Appearances can be misleading. The proverb warns against forming opinions from looks alone.
2. Which sentence uses the proverb correctly?
Answer: The old car looked rough but ran perfectly; don't judge a book by its cover.. The proverb fits cases where looks are misleading, not where looks match reality.
Similar idioms
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