Spy bumping off a bloke (4)
I believe the answer is:
gent
'bloke' is the definition.
(I've seen this in other clues)
'spy bumping off a' is the wordplay.
'spy' becomes 'agent' (I've seen this before).
'bumping off' is a deletion indicator.
'agent' with 'a' removed is 'GENT'.
(Other definitions for gent that I've seen before include "bloke" , "Informal and short man" , "Refined man (colloquial)" , "Chap, fellow" , "Man of good standing (informal)" .)