___ interface (4)
I believe the answer is:
user
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">interface</span>' is the definition.<br/ ><span class="explanation-format__explanation">(user interface is a kind of interface)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for user that I've seen before include "Manipulator" , "Maybe one needing pot" , "Consumer" , "One who exploits, to be sure" , "Druggie" .)