Source : Webster's Revised Unabridged Dictionary (1913)

Buoyant \Buoy"ant\, a. [From {Buoy}, v. t. & i.]
   1. Having the quality of rising or floating in a fluid;
      tending to rise or float; as, iron is buoyant in mercury.
      ``Buoyant on the flood.'' --Pope.

   2. Bearing up, as a fluid; sustaining another body by being
      specifically heavier.

            The water under me was buoyant.       --Dryden.

   3. Light-hearted; vivacious; cheerful; as, a buoyant
      disposition; buoyant spirits. -- {Buoy"ant*ly}, adv.

Source : WordNet®

buoyantly
     adv : in a cheerfully buoyant manner; "we accepted the opportunity
           buoyantly" [syn: {chirpily}]