Meaning: Someone who faults another for faults conspicuously his own.
Example: You think police should stop all those other terrible drivers? That's like the pot calling the kettle black!
Origin: This expression dates back to the 17th Century. In ancient times, pots as well as kettles would likely be blackened over the open cooking fires of the day.
Alternative: "The pot calling the kettle black: Said of someone accusing another of faults similar to those committed by the accuser. The allusion is to the old household in which the copper kettle would be kept polished, while the iron pot would remain black. The kettle's bright side would reflect the pot. The pot, seeing its reflection, would thus see black, which would appear to be on the side of the kettle. The pot could then accuse the kettle of a fault it did not have." Source: Brewer's Dictionary of Phrase and Fable, 1870, revised by Adrian Room (Millennium Edition)