Noble spy (4)
I believe the answer is:
peer
I believe this clue is a double definition.
'noble' is the first definition.
(peers are members of the nobility)
'spy' is the second definition.
(peer can mean to look at or spy on)
(Other definitions for peer that I've seen before include "Look closely - nobleman" , "Social equal" , "Look dimly at lord" , "Squint" , "Look closely at titled man?" .)