Badly sullied? (3-4)
I believe the answer is:
ill-used
'badly sullied?' is the definition.
Although both the answer and definition are past participle verbs, I can't see how one could define the other.
'badly sullied?' is the wordplay.
'badly' is an anagram indicator.
'sullied' is an anagram of 'ILL-USED'.
(Other definitions for ill-used that I've seen before include "Mistreated" , "Maltreated" , "Badly treated, exploited" .)