The term 'Didn't Tip' is often used to describe a situation in which a customer does not leave a tip for a service provider. The crossword solution for this term is 'STIFFED', which means to have been cheated or defrauded out of something, such as money or a tip. This term is often used in the context of a customer not leaving a tip for a service provider, thus 'stiffing' them out of the money they were expecting.