Moody, volatile (13)
I believe the answer is:
temperamental
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">moody</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that moody can be written as temperamental)</span><br/ ><br/ >'<span class="explanation-format__original">volatile</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for temperamental that I've seen before include "requiring delicate handling" , "Liable to mood swings" , "Difficult" , "Unreliable" , "Touchy, moody" .)