buoyancy

nouns

cheerfulness that bubbles to the surface
buoyancy, perkiness
is derived from
buoyant
the property of something weightless and insubstantial
airiness, buoyancy
is derived from
buoyant
the tendency to float in water or other liquid
buoyancy
is a type of (narrower)
a characteristic likelihood of or natural disposition toward a certain condition or character or effect
"the alkaline inclination of the local waters"; "fabric with a tendency to shrink"
inclination, tendency
irrepressible liveliness and good spirit
"I admired his buoyancy and persistent good humor"
buoyancy, irrepressibility
is derived from
buoyant