Glum drop? (4)
I believe the answer is:
tear
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">glum drop?</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 tear that I've seen before include "Shred" , "A drop of optical moisture" , "Rip apart; drop" , "Rent - drop" , "speed" .)