Unnecessarily (10)
I believe the answer is:
needlessly
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unnecessarily</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 needlessly that I've seen before include "Unnecessarily" , "without any necessity" , "without justification" , "without good reason" .)