Cause of great distress (4)
I believe the answer is:
bane
'cause of great distress' is the definition.
(I've seen this before)
This is the entire clue.
(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" .)