You can't judge a book by its cover

You can't judge a book by its cover.

something that you say which means you cannot judge the quality or character of someone or something just by looking at them She doesn't look very intelligent, but you can't judge a book by its cover.
See also: book, cover, judge
References in periodicals archive ?
As the saying goes, you can't judge a book by its cover.
The old saying is true: sometimes, you can't judge a book by its cover.
COOL DWELLINGS: Encino might not appreciate being called ``ordinary'' on the cover of the first anniversary issue of Dwell, but the Valley house featured inside demonstrates that you can't judge a book by its cover.
If there's any lesson the Barbis would have you learn, it's that you can't judge a book by its cover.
The myth that consumer debt is evil is as suspect as the bromide that you can't judge a book by its cover.
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