Trick joint is a slang term for a place where illegal activities take place, such as gambling or drug dealing. It is often used to refer to a bar or club that has been taken over by criminals. The crossword solution for the term 'trick joint' is 'KNEE, ' which refers to the joints in the body where the bones meet. This is likely a reference to the idea of a person being 'on their knees' when they are involved in criminal activity.