Wish it weren't so (3)
I believe the answer is:
rue
'wish it weren't so' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rue that I've seen before include "Fish eggs" , "Regret; road (Fr.)" , "Regret or repent" , "French way" , "The 'herb of grace'" .)