don't judge a book by its cover

Meaning

This idiom means you should not form an opinion about the value or character of something or someone based purely on their outward appearance. It suggests that things are often much deeper or different than they look at first glance. It is commonly used as a piece of advice or a reminder.

Examples

• The restaurant looked tiny and run-down, but the food was amazing—don't judge a book by its cover.

  The restaurant looked tiny and run-down, but the food was amazing—don't judge a book by its cover.

• She seemed very quiet and shy, but she is actually a bold leader; you really can't judge a book by its cover.

  She seemed very quiet and shy, but she is actually a bold leader; you really can't judge a book by its cover.

• The hotel lobby was beautiful, but the rooms were terrible, proving you shouldn't judge a book by its cover.

  The hotel lobby was beautiful, but the rooms were terrible, proving you shouldn't judge a book by its cover.

• Don't judge a book by its cover; that old car is actually incredibly fast and reliable.

  Don't judge a book by its cover; that old car is actually incredibly fast and reliable.

• He might look intimidating, but he's a sweetheart, so don't judge a book by its cover.

  He might look intimidating, but he's a sweetheart, so don't judge a book by its cover.

Common Mistakes

• ✗ Don't judge a book from its cover.

  ✓ Don't judge a book by its cover.

  The correct preposition in this idiom is always 'by', not 'from'.

• ✗ You shouldn't judge the book by its cover.

  ✓ You shouldn't judge a book by its cover.

  The idiom uses the indefinite article 'a book', not the definite article 'the book'.

Related Expressions

Practice

• The house looks terrible from the outside, but inside it's gorgeous. Truly, ___.

  💡 Appearances can be misleading

  Show answer

  don't judge a book by its cover

• He doesn't look like a typical athlete, but ___.

  💡 Do not form opinions based on looks

  Show answer

  don't judge a book by its cover