The Collaborative International Dictionary of English v.0.48:

Vivacious \Vi*va"cious\ (?; 277), a. [L. v['i]vax, -acis, fr.
   vivere to live. See Vivid.]
   1. Having vigorous powers of life; tenacious of life;
      long-lived. [Obs.]
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            Hitherto the English bishops have been vivacious
            almost to wonder. . . . But five died for the first
            twenty years of her [Queen Elizabeth's] reign.
                                                  --Fuller.
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            The faith of Christianity is far more vivacious than
            any mere ravishment of the imagination can ever be.
                                                  --I. Taylor.
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   2. Sprightly in temper or conduct; lively; merry; as, a
      vivacious poet. "Vivacious nonsense." --V. Knox.
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   3. (Bot.) Living through the winter, or from year to year;
      perennial. [R.]
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   Syn: Sprightly; active; animated; sportive; gay; merry;
        jocund; light-hearted.
        [1913 Webster] -- Vi*va"cious*ly, adv. --
        Vi*va"cious*ness, n.
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