Cause of great distress (4)
I believe the answer is:
bane
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cause of great distress</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for bane that I've seen before include "Cause of distress, ruin" , "Cause of great distress, rhymes with rule" , "Cause of trouble or worry, like bean" , "Cause of trouble or anxiety" , "A fatal poison" .)