"Smooth Operator" singer (4)
I believe the answer is:
sade
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">smooth operator singer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sade that I've seen before include "The Marquis de . . . . was noted for cruelty" , "Marquis de ..., famous for taking pleasure in pain" , "Jazz-pop group" , "letter from Israel?" , "Hebrew character" .)