buoy·an·cy 
(boiən-sē, byən-)
(boiən-sē, byən-)n.
1.
a. The tendency or capacity to remain afloat in a liquid or rise in air or gas.
b. The upward force that a fluid exerts on an object less dense than itself.
2. Ability to recover quickly from setbacks; resilience.
3. Lightness of spirit; cheerfulness.