Look to see one's equal (4)
I believe the answer is:
peer
I believe this is a double definition.
'look' is the first definition.
(to peer at something is to look at it)
'one's equal' is the second definition.
(I've seen this before)
'to see' is the link.
(Other definitions for peer that I've seen before include "Look dimly at lord" , "Noble; look intently" , "Look; earl" , "Look hard at the nobleman" , "Aristocrat" .)