Foolishness, inanity (9)
I believe the answer is:
asininity
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">foolishness</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that asininity is a type of foolishness)</span><br/ ><br/ >'<span class="explanation-format__original">inanity</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for asininity that I've seen before include "Stupidity" , "Extreme foolishness" , "Idiocy" , "Foolishness as of donkey" .)