Iniquitous (4)
I believe the answer is:
evil
'iniquitous' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for evil that I've seen before include "Harmful; unlucky" , "'The ... that men do lives after them' (Shakespeare)" , "mischief" , "Extremely wicked" , "Immorality" .)