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.