Okay but not quite entirely correct? (7)
I believe the answer is:
alright
'okay' is the definition.
('alright' can be a synonym of 'okay')
'not quite entirely correct?' is the wordplay.
'not quite' means to remove the last letter.
'entirely' becomes 'all' (I've seen this before).
'correct?' becomes 'right' ('right' can be a synonym of 'correct').
'all' with its final letter removed is 'al'.
'al'+'right'='ALRIGHT'
'but' acts as a link.
(Other definitions for alright that I've seen before include "Acceptable" , "OK, as some would have it" , "satisfactory for some of us" , "Okay" , "Fine; agreed" .)