Exploiter (4)
I believe the answer is:
user
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">exploiter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for user that I've seen before include "Drug addict (colloq.)" , "Person who takes drugs" , "Patron" , "Utiliser" , "Right long-established" .)