levity

noun4

1. •
   A lightness of manner or speech, frivolity; flippancy; a lack of appropriate seriousness; an inclination to make a joke of serious matters.

   • An attempt to inject a little levity into the proceedings.
2. •
   A lighthearted or frivolous act.

   • […] or do the people joy less than common in their levities?" — 1872
3. •
   The state or quality of being light, buoyancy.

   • Most of the confidences were unsought - frequently I have feigned sleep, preoccupation or a hostile levity […] — 1925
4. •
   (no longer used) A lack of steadiness.