Vigor

Vig"or (?), n. [OE. vigour, vigor, OF. vigor, vigur, vigour, F. vigueur, fr. L. vigor, fr. vigere to be lively or strong. See Vegetable, Vigil.] 1. Active strength or force of body or mind; capacity for exertion, physically, intellectually, or morally; force; energy.

The vigor of this arm was never vain.
Dryden.

2. Strength or force in animal or force in animal or vegetable nature or action; as, a plant grows with vigor.

3. Strength; efficacy; potency.

But in the fruithful earth . . .
His beams, unactive else, their vigor find.
Milton.

Vigor and its derivatives commonly imply active strength, or the power of action and exertion, in distinction from passive strength, or strength to endure.

Vig"or, v. t. To invigorate. [Obs.] Feltham.