Meaning Decisions can't be made solely on appearance.
Usage Worldwide.
Example
- Raphael Nadal looked like he was straight from a street gang. I guess you can't judge a book by its cover.
Pronunciation
Idiom
You cant judge a book by its cover
What does "You cant judge a book by its cover" mean?
Decisions can't be made solely on appearance.
You can’t judge a book by its cover
Britain, 19th century.