Sleep lightly (4)
I believe the answer is:
doze
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sleep lightly</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 doze that I've seen before include "Take forty winks" , "Catnap" , "Sleep fitfully" , "Nod off" , "A short light sleep" .)