Lewis & Short

vīvācĭtas, ātis, f. [vivax].

  1. I. Natural vigor, vital force, tenaciousness or length of life, vivaciousness (post-Aug.): tam angustis terminis tantae multitudinis vivacitas continetur, Plin. Ep. 3, 7, 13; Col. 11, 3, 41; Plin. 8, 24, 41, § 101; Quint. 6, praef. 3; Val. Max. 8, 13, ext. 4; Tert. Anim. 25.
    Plur., App. de Mundo, 58, 15.
  2. II. Liveliness, vivacity: ingenii, Arn. 5, 179; cf. id. 2, 45: cordis, id. 5, 157.