Unimportance (14)
I believe the answer is:
insignificance
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unimportance</span>' is the definition.<br/ ><span class="explanation-format__explanation">(insignificance is a kind of unimportance)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for insignificance that I've seen before include "Unimportance" , "The quality of trifles" .)