The idiom the pot calling the kettle black means that someone is accusing or criticizing someone else of a fault or flaw that they themselves have. It is an example of hypocrisy or psychological projection. The idiom may have originated in Spanish, and the first English version appeared in the 1620 translation of Don Quixote by Thomas Shelton. The idiom is based on the idea that both the pot and the kettle are blackened by the same fire, so the pot has no right to judge the kettle for being black. Another interpretation is that the pot sees its own black reflection on the shiny surface of the kettle, and mistakenly thinks that the kettle is black.
