A boy as an individual (6)
I believe the answer is:
person
'an individual' is the definition.
('person' can be a synonym of 'individual')
'a boy' is the wordplay.
'a' becomes 'per'.
'boy' becomes 'son' ('son' can be a synonym of 'boy'**).
'per'+'son'='PERSON'
'as' is the link.
(Other definitions for person that I've seen before include "Bod" , "present appearing in this" , "he's the third" , "Type" , "anyone else" .)