vt & ·vi bearing up, as a fluid; sustaining another body by being specifically heavier.
2. buoyant ·vt & ·vi light-hearted; vivacious; cheerful; as, a buoyant disposition; buoyant spirits.
3. buoyant ·vt & ·vi having the quality of rising or floating in a fluid; tending to rise or float; as, iron is buoyant in mercury.