This means that no one is better at finding a wrongdoer than another wrongdoer. So if you do something wrong, then you would know if someone else followed your mistake, or you would know someone with the same quality as yourself, did the same mistake if that makes any sense lmao. The example will help better your understanding.
by GrammarQueen August 24, 2017
"You're a whore."
"Takes one to know one!"
"That doesn't change the fact that you spread your legs for money."
"Takes one to know one!"
"That doesn't change the fact that you spread your legs for money."
by Treeeees January 25, 2010