Good copy — stare in wonder (4)
I believe the answer is:
gape
'stare in wonder' is the definition.
(I've seen this in another clue)
'good copy' is the wordplay.
'good' becomes 'g' (abbreviation).
'copy' becomes 'ape' (ape can mean to copy or imitate).
'g'+'ape'='GAPE'
(Other definitions for gape that I've seen before include "Yawn" , "Stare with open mouth in wonder" , "Look with mouth wide open" , "watch in wonder" , "Appear amazed" .)