Has prep to revise, maybe (7)
I believe the answer is:
perhaps
'maybe' is the definition.
('perhaps' can be a synonym of 'maybe')
'has prep to revise' is the wordplay.
'to revise' is an anagram indicator.
'has'+'prep'='hasprep'
'hasprep' with letters rearranged gives 'PERHAPS'.
(Other definitions for perhaps that I've seen before include "Could be, maybe" , "Conceivably" , "say" , "Possibly but not certainly" , "Not necessarily" .)