Unleaded is a type of fuel that is used in motor vehicles. It is a gasoline-based fuel that does not contain lead additives, which were commonly used in the past to increase octane levels. The term 'unleaded' is often used interchangeably with 'REGULAR' gasoline, as it is the most common type of fuel used in cars and other motor vehicles. The crossword solution for the term 'unleaded' is DECAF, which stands for 'diethyl ether and cyclohexane free'.