Looking amazed by a good turn around (4)
I believe the answer is:
agog
'looking amazed' is the definition.
(I've seen this before)
'a good turn around' is the wordplay.
'a good' becomes 'ag' (I've seen this in other clues).
'turn' becomes 'go' (a person's move in a board game).
'around' shows that the letters should be reversed in order.
'go' back-to-front is 'og'.
'ag'+'og'='AGOG'
'by' is the link.
(Other definitions for agog that I've seen before include "Eager - in suspense" , "Eagerly expectant" , "Very eager (to hear/see)" , "All ears" , "Eagerly excited" .)