show one's true colors


Reveal oneself as one really is, as in We always thought he was completely honest, but he showed his true colors when he tried to use a stolen credit card. This expression alludes to the antonym, false colors, that is, sailing under a flag other than one's own. [Late 1700s]

QUIZZES

LEARN THE SPANISH WORDS FOR THESE COMMON ANIMALS!

Are you learning Spanish? Or do you just have an interest in foreign languages? Either way, this quiz on Spanish words for animals is for you.
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How do you say “cat” 🐈 in Spanish?
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.