The term 'CERTAIN SUGAR SUBSTITUTE' can be solved by the five-letter word 'HONEY'. HONEY is a natural sweetener that has been used for centuries as a sugar substitute. It is made by bees from the nectar of flowers and is composed of fructose, glucose, and water. HONEY has a unique flavor and is often used in baking and cooking. It is also known to have health benefits, such as being a source of antioxidants and providing antibacterial properties.