Sort family feud at last (4)
I believe the answer is:
kind
'sort' is the definition.
(synonyms)
'family feud at last' is the wordplay.
'family' becomes 'kin' (synonyms).
'at last' indicates one should take the final letters.
The last letter of 'feud' is 'd'.
'kin'+'d'='KIND'
(Other definitions for kind that I've seen before include "Type; good-hearted" , "Class, type" , "caring" , "Generously disposed" , "Benevolent - sort" .)