The crossword solution for the term 'EXTREME ENERGY' is ARDOR, which is a five-letter word. ARDOR is defined as intense and passionate feeling or enthusiasm. It is often used to describe strong emotions such as love, anger, or zeal. ARDOR is also used to describe an intense energy or enthusiasm for something. In this context, it can be used to describe extreme energy, which is a powerful force that can be used to accomplish great things.