Vigor

1. v. t. To invigorate.
2. n. Active strength or force of body or mind; capacity for exertion, physically, intellectually, or morally; force; energy.
3. n. Strength or force in animal or force in animal or vegetable nature or action; as, a plant grows with vigor.
4. n. Strength; efficacy; potency.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.