Groucho-type look (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">groucho-type look</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 leer that I've seen before include "Give lascivious look" , "Stare suggestively" , "Lascivious gaze" , "Suggestive or sneering grin" , "Gaze lasciviously at" .)