Study again (6)
I believe the answer is:
reread
'study again' is the definition.
('read' can be a synonym for 'study' so perhaps 'reread' is OK for 'study again')
This is the entire clue.
(Other definitions for reread that I've seen before include "Peruse or scan again; it's dearer" , "Give script second seeing to" , "Study text again" , "Perused again" , "look again at manifesto?" .)