vigour

noun3

1. •
   Active strength or force of body or mind; a capacity for exertion, physically, intellectually, or morally; energy.

   • The vigour of this arm was never vain — 1717
2. •
   Strength or force in animal or vegetable nature or action.

   • A plant grows with vigour.
3. •
   Strength; efficacy; potency.

   • But in the fruithful earth: there first receiv'd / His beams, unactive else, their vigour find. — 1667