Morally wrong or bad (4)
I believe the answer is:
evil
This clue is a double definition.
'morally wrong' is the first definition.
(I've seen this in another clue)
'bad' is the second definition.
(I know that evil is a type of bad)
(Other definitions for evil that I've seen before include "Malignant" , "Vile (anag) -- really bad" , "Extremely unpleasant" , "very naughty" , "Unholy" .)