What does "vivacity" mean?

Vivacity: The quality or state of being vivacious. Specifically: -- (a) Tenacity of life; vital force; natural vigor. [Obs.] The vivacity of some of these pensioners is little less than a miracle, they lived so long. Fuller. (b) Life; animation; spiritedness; liveliness; sprightliness; as, the vivacity of a discourse; a lady of great vivacity; vivacity of countenance. See Liveliness.