Neither masculine nor feminine (6)
I believe the answer is:
neuter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">neither masculine nor feminine</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 neuter that I've seen before include "De-sex" , "Neither male nor female" , "Make ineffective; gender" , "Castrate" , "Of noun, neither masculine nor feminine" .)