Not entirely a country boy (4)
I believe the answer is:
alan
'boy' is the definition.
(I've seen this before)
'not entirely a country' is the wordplay.
'not entirely' means to remove the last letter.
'country' becomes 'land' ('land' can be a synonym of 'country').
'a'+'land'='aland'
'aland' with its last letter taken away is 'ALAN'.
(Other definitions for alan that I've seen before include "A.A. Milne's first name" , "Sir -- Sugar (The Apprentice)" , "- Ayckbourn, English playwright" , "English historian/poet" , "- Bates, - Bennett" .)