Item, fine and good (5)
I believe the answer is:
thing
'item' is the definition.
(both can mean an object)
'fine and good' is the wordplay.
'fine' becomes 'thin' (similar in meaning).
'and' says to put letters next to each other.
'good' becomes 'g' (abbreviation).
'thin'+'g'='THING'
(Other definitions for thing that I've seen before include "Affair - matter" , "cup of tea" , "See 1" , "Unspecified object" , "Body" .)