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;
Hitherto the English bishops have been vivacious
almost to wonder. . . . But five died for the first
twenty years of her [Queen Elizabeth's] reign.
The faith of Christianity is far more vivacious than
any mere ravishment of the imagination can ever be.
2. Sprightly in temper or conduct; lively; merry; as, a
vivacious poet. "Vivacious nonsense." --V. Knox.
3. (Bot.) Living through the winter, or from year to year;
Syn: Sprightly; active; animated; sportive; gay; merry;
[1913 Webster] -- Vi*va"cious*ly, adv. --