buoyancy

noun3

1. •
   The ability of an object to stay afloat in a fluid.
2. •
   The upward force on a body immersed or partly immersed in a fluid.
3. •
   (figurative) Resilience or cheerfulness.

   • With how much lighter a step, with how much brighter an eye, did Francesca wander through the forest, even in the last desolation of autumn, than she did in all the bloom and buoyancy of spring! — 1834