Lustful desire (6)
I believe the answer is:
libido
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lustful desire</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for libido that I've seen before include "Emotional energy associated with sexual desire" , "Emotional craving" , "I'd boil over with sexual energy" , "Sexual drive" , "Strong urge" .)