Cunningly clever (6)
I believe the answer is:
artful
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cunningly clever</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 artful that I've seen before include "Crafty or cunning" , "Cunning, wily" , "Oliver Twist's pal was an . . . . . . dodger" , "Crafty like Dicken's Dodger" , "Unnatural - cunning" .)