Private meal hasn't started (5)
I believe the answer is:
'private' is the definition.
(as in one's private or inner thoughts)
'meal hasn't started' is the wordplay.
'meal' becomes 'dinner' (dinner is a kind of meal).
'hasn't started' means to remove the first letter.
'dinner' with its initial letter taken off is 'INNER'.
(Other definitions for inner that I've seen before include "Annulus nearest bull" , "Not a bad shot" , "Close to the centre; mental" , "may not satisfy this man" , "Opposite of 13" .)