| Noun | 1. | buoyancy - cheerfulness that bubbles to the surfaceblitheness, cheerfulness - a feeling of spontaneous good spirits; "his cheerfulness made everyone feel better" | |
| 2. | buoyancy - the property of something weightless and insubstantial | |
| 3. | buoyancy - irrepressible liveliness and good spirit; "I admired his bouyancy and persistent good humor" | |