The term 'Flying off the Shelves' is used to describe a product that is SELLING very quickly. This phrase can be broken down into three crossword solutions: HOT (3 letters), SELLING (7 letters), and REDHOT (6 letters). HOT is an adjective used to describe something that is very popular or in demand, while SELLING is a verb that describes the act of exchanging goods or services for money. REDHOT is an intensifier that emphasizes the degree of popularity or demand for a product. Together, these three words paint a picture of a product that is extremely popular and SELLING quickly.