healthy physical or mental energy or power; vitality.
3.
energetic activity; energy; intensity: The economic recovery has given the country a new vigor.
4.
force of healthy growth in any living matter or organism, as a plant.
5.
active or effective force, especially legal validity.
Also, especially British, vig·our.
Origin: 1300–50; Middle English vigo(u)r < Anglo-French; Middle French vigeur < Latin vigor force, energy, equivalent to vig(ēre) to be vigorous, thrive + -or-or1
c.1300, from Anglo-Fr. vigour, O.Fr. vigor, from L. vigorem (nom. vigor) "liveliness, activity, force," from vigere "be lively, flourish, thrive," from PIE *wog-/*weg- "be lively or active" (see vigil).