Frivolity (6)
I believe the answer is:
levity
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">frivolity</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that levity is a type of frivolity)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for levity that I've seen before include "Light-heartedness" , "Unseriousness" , "Facetiousness" , "Disrespectful treatment of a serious matter" , "Lack of seriousness" .)