liveliness; animation; sprightliness: a people noted for their vivacity.
3.
a vivacious act or statement.
Origin: 1400–50; late ME < L vīvācitās, equiv. to vīvāc- (s. of vīvāx long-lived, lively, equiv. to vīv(us) alive (see vital) + -āx adj. suffix) + -i--i-+ -tās-ty2
vi·vac·i·ty (vĭ-vās'ĭ-tē, vī-) n. The quality or condition of being vivacious; liveliness: "the light and vivacity that laugh in the eyes of a child"(Charles Dickens).
1432, from L. vivacitatem (nom. vivacitas) "vital force, liveliness," from vivax (gen. vivacis) "lively," also "long-lived," from vivere "to live" (see vital). Vivacious is first recorded c.1645.