Bird with new or old coin (5)
I believe the answer is:
crown
'old coin' is the definition.
(I've seen this before)
'bird with new' is the wordplay.
'bird' becomes 'crow' (crow is a kind of bird).
'with' means one lot of letters go next to another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'crow'+'n'='CROWN'
'or' acts as a link.
(Other definitions for crown that I've seen before include "repair for damaged tooth" , "The sovereign" , "Highest part; coin" , "Visible part of a tooth" , "peak" .)