James Bond, for one (3)
I believe the answer is:
'james bond for one' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for spy that I've seen before include "Discover" , "Person who secretly collects information as for government" , "Enemy agent" , "Watch covertly like secret agent" , "Keep watch secretly, maybe for foreign government" .)