Enemy's cover protected by spy on the other side (6)
I believe the answer is:
beyond
'enemy's cover protected' is the definition.
I can't tell whether this definition defines the answer.
'spy on the other side' is the wordplay.
'spy' becomes 'bond' (James Bond).
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'the other side' becomes 'ey' (I am not sure about this - if you are sure you should believe this answer much more).
'bond' enclosing 'ey' is 'BEYOND'.
'by' acts as a link.
Can you help me to learn more?
(Other definitions for beyond that I've seen before include "On the far side of" , "Better than" , "unknown" , "On the farther side - in addition" , "Outside the range of" .)