Powerful emotion
I believe the answer is:
love
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">powerful emotion</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 love that I've seen before include "Serenade" , "Zero (that makes the world go round?)" , "0 (tennis)" , "like very much?" , "associated with a cold climate?" .)