The term 'APPRECIATIVE DINER' can be broken down into two crossword solutions: 'TIPPER' (6 letters) and 'DINER' (5 letters). A tipper is someone who gives a gratuity or tip to a service worker, such as a waiter or waitress, in appreciation for their services. A DINER is a small restaurant that typically serves American cuisine. Therefore, an 'appreciative DINER' is someone who visits a DINER and tips the service workers in appreciation for their services.