The Collaborative International Dictionary of English v.0.48:

Vivacity \Vi*vac"i*ty\, n. [L. vivicitas: cf. F. vivacit['e].]
   The quality or state of being vivacious. Specifically:
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   (a) Tenacity of life; vital force; natural vigor. [Obs.]
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             The vivacity of some of these pensioners is little
             less than a miracle, they lived so long. --Fuller.
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   (b) Life; animation; spiritedness; liveliness; sprightliness;
       as, the vivacity of a discourse; a lady of great
       vivacity; vivacity of countenance.
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   Syn: Liveliness; gayety. See Liveliness.
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WordNet (r) 3.0 (2006):

vivacity
    n 1: characterized by high spirits and animation