Canny (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">canny</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 shrewd that I've seen before include "... knowing" , "Canny and with sound judgement" , "sharp" , "Astute or crafty" , "Astute, clever" .)