Want some grades — I revised (6)
I believe the answer is:
desire
'want' is the definition.
('desire' can be a synonym of 'want')
'some grades i revised' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'DESIRE' is hidden in the letters of 'grades i revised'.
(Other definitions for desire that I've seen before include "Want strongly" , "Wish for strongly" , "Lust" , "Want, wish for" , "Long for (something)" .)