Of small importance (5)
I believe the answer is:
minor
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">of small importance</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for minor that I've seen before include "Paltry" , "One hasn't reached legal majority" , "Unimportant or unable to vote" , "Junior" , "Slight; little known" .)