it takes one to know one

it takes one to know one idiom
The person who expressed criticism has similar faults to the person being criticized. This classic retort to an insult dates from the early 1900s. For example, You say she's a terrible cook? It takes one to know one! For a synonym, see pot calling the kettle black. A near equivalent is the proverbial it takes a thief to catch a thief, meaning “no one is better at finding a wrongdoer than another wrongdoer.” First recorded in 1665, it remains current.

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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