Kind to fat fiancée suffering abuse (12)
I believe the answer is:
affectionate
'suffering abuse' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
'kind to fat fiancee' is the wordplay.
'kind' indicates an anagram (I've seen 'kind of' mean this).
'to'+'fat'+'fiancee'='tofatfiancee'
'tofatfiancee' is an anagram of 'AFFECTIONATE'.
Can you help me to learn more?
(Other definitions for affectionate that I've seen before include "Warm-hearted - loving" , "friendly" , "Tender" , "Fond" , "Expressing fondness" .)