It takes one to know one. I mean that's what it means , I wasn't calling you a pot. The kettle could answer, "Look who's talking." It goes way back to when cooking was done over fires. If the pot and kettle weren't already black cast iron when new they were soon black from the soot and smoke. The black has nothing to do with 'evil' or race. Usually though, there is a connotation of criticism in both the use of "black" and in the entire phrase. The pot is being hypocritical , criticising the kettle for a quality or action or something that the pot itself has. It's not as strong as Jesus' "log in the eye" analogy, where the critcizer has a bigger flaw than the criticized . If you wanta analyze it a bit more, you could move forward in time to when pots were still cast iron but kettles were being made of tin or other 'white' metals. Then the pot is criticising the kettle for becoming something the pot has always been. Or... the pot was black but the kettle shiny, the pot sees its own reflection in the shiny surface of the kettle and claims that the kettle, not it, was black. But the saying goes back to before white shiny kettles . If someone who spends all day answering questions here in the bag critcizes someone else who spends all day answering questions ( ahem) by saying " you have too much time on your hands," then the pot is calling the kettle black.