U grades changed and sweetened (7)
I believe the answer is:
sugared
'sweetened' is the definition.
(I know that sweetened can be written as sugared)
'u grades changed' is the wordplay.
'changed' indicates anagramming the letters.
'u'+'grades'='ugrades'
'ugrades' with letters rearranged gives 'SUGARED'.
'and' is the link.
(Other definitions for sugared that I've seen before include "Sweetly coated (almond)" , "Sweetened" .)