Surpass everything, but not entirely great (7)
I believe the answer is:
capital
'great' is the definition.
('capital' can be a synonym of 'great')
'surpass everything but not entirely' is the wordplay.
'surpass everything' becomes 'capitall' (to 'cap it all' can mean to surpass everything).
'but not entirely' means to remove the last letter.
'capitall' with its last letter taken away is 'CAPITAL'.
(Other definitions for capital that I've seen before include "Principal city" , "Cardiff, say" , "high in architecture" , "Fantastic!" , "liquid assets" .)