Energy

1. Strength of expression; force of utterance; power to impress the mind and arouse the feelings; life; spirit; -- said of speech, language, words, style; as, a style full of energy.
2. Power efficiently and forcibly exerted; vigorous or effectual operation; as, the energy of a magistrate.
3. Internal or inherent power; capacity of acting, operating, or producing an effect, whether exerted or not; as, men possessing energies may suffer them to lie inactive.
4. Capacity for performing work.