"The pot calling the kettle black" is an idiomatic expression that means a situation in which somebody accuses someone else of a fault which the accuser shares. The phrase is often used to point out hypocrisy, as it suggests that the accuser is guilty of the same fault they are criticizing in the other person. The origin of the phrase is uncertain, but it has been used in English since at least the 17th century. The phrase is still commonly used in both formal and informal settings, and it is not considered outdated or offensive by young people.