Astonished to be punched in the face (10)
I believe the answer is:
gobsmacked
'astonished' is the definition.
(I've seen this before)
'be punched in the face' is the wordplay.
I cannot quite see how this works, but
'be' could be 'go' (going is a kind of being) and 'go' is present in the answer.
This explanation may well be incorrect...
'to' acts as a link.
(Other definitions for gobsmacked that I've seen before include "bowled over" , "shocked" , "Dumbfounded" , "Amazed" , "Astounded" .)