Buoyant

·vt & ·vi Bearing up, as a fluid; sustaining another body by being specifically heavier.

II. Buoyant ·vt & ·vi Light-hearted; vivacious; cheerful; as, a buoyant disposition; buoyant spirits.

III. Buoyant ·vt & ·vi Having the quality of rising or floating in a fluid; tending to rise or float; as, iron is buoyant in mercury.