Ophelia gives details to her father about how Hamlet has expressed love to her, “With almost all the holy vows of heaven.” Polonius tells her that his words “blazes” means their love which is insincere. It also means “flares and flashes.” They give more light than heat “extinct in both” means both lack light and heat. They figuratively lack genuine emotion and honesty. He further says that, “You must not take [these blazes] for fire”. By this he means Hamlet is merely using insincere words to seduce his naïve and innocent daughter.