Tousle, as the hair, is a term used to describe the act of running one's fingers through the hair to create a disheveled look. The term is derived from the French verb tousser, which means 'to shake or move.' This hairstyle has been popularized by celebrities and is often seen on the red carpet. The crossword solution for this term is 'MUSS, ' which is a four-letter verb meaning to mess up or disarrange.