Mindlessness
I believe the answer is:
inanity
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mindlessness</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that mindlessness can be written as inanity)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for inanity that I've seen before include "Being silly" , "Puerility" , "Silliness in a tiny way" , "Foolishness" , "Folly" .)