Look lasciviously (4)
I believe the answer is:
leer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">look lasciviously</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 leer that I've seen before include "Lewd look" , "Gaze lasciviously at" , "Suggestive or sneering look" , "Look suggestively" , "Look lasciviously at" .)