The term 'Quiet Type' can be described by two crossword solutions: MIME (4 letters) and MOUSE (5 letters). A MIME is a performer who communicates through body language, gestures, and facial expressions without speaking. This type of performance art has been around since ancient Greece and Rome, and is still popular today. A MOUSE is a small rodent that is known for its quietness. It is also the name of a computer input device that is used to control the cursor on a screen. Both of these solutions are appropriate for describing someone who is a 'Quiet Type'.