Foreign Office axes cunning (4)
I believe the answer is:
foxy
'cunning' is the definition.
(I know that cunning can be written as foxy)
'foreign office axes' is the wordplay.
'foreign office' becomes 'FO' (abbreviation).
'axes' becomes 'xy' (x axis and y axis).
'fo'+'xy'='FOXY'
(Other definitions for foxy that I've seen before include "Vulpine; sly" , "Sly -- sexy" , "Cunning - sexually attractive" , "tricky" , "Hot" .)