Activity \Ac*tiv"i*ty\, n.; pl. {Activities}. [Cf. F. activit['e], LL. activitas.] The state or quality of being active; nimbleness; agility; vigorous action or operation; energy; active force; as, an increasing variety of human activities. ``The activity of toil.'' --Palfrey. Syn: Liveliness; briskness; quickness.