Shilling next to copper (5)
I believe the answer is:
bobby
'copper' is the definition.
(I know that copper can be written as bobby)
'shilling next to' is the wordplay.
'shilling' becomes 'bob' (I've seen this in another clue).
'next to' becomes 'by'.
'bob'+'by'='BOBBY'
(Other definitions for bobby that I've seen before include "beat man" , "Rob" , "- Moore, World Cup winning captain" , "Policeman (sl.)" , "Peeler" .)