Won't emend revised bequest (9)
I believe the answer is:
endowment
'bequest' is the definition.
(thesaurus)
'won't emend revised' is the wordplay.
'revised' indicates anagramming the letters.
'wont'+'emend'='wontemend'
'wontemend' anagrammed gives 'ENDOWMENT'.
(Other definitions for endowment that I've seen before include "Grant" , "Personal quality - type of mortgage" , "one's landed with?" , "Bequeathed income" , "source of income" .)