Goodness! Note damaged headdress (7)
I believe the answer is:
coronet
'headdress' is the definition.
(coronet is a kind of headdress)
'goodness note damaged' is the wordplay.
'goodness' becomes 'cor' (both are exclamations of surprise).
'damaged' indicates an anagram.
'note' is an anagram of 'onet'.
'cor'+'onet'='CORONET'
(Other definitions for coronet that I've seen before include "brass embellishment" , "Diadem" , "Peer's headgear" , "sign of rank" , "jewelled headdress" .)