Cheats men, reversing sanctions (5)
I believe the answer is:
rooks
'cheats' is the definition.
(rooking is a kind of cheating)
'men reversing sanctions' is the wordplay.
'men' becomes 'or' (military abbreviation for Other Ranks).
'reversing' says the letters should be written backwards.
'sanctions' becomes 'oks' ('ok' can be a synonym of 'sanction').
'or' reversed gives 'ro'.
'ro'+'oks'='ROOKS'
(Other definitions for rooks that I've seen before include "Chess pieces or black birds" , "Collective name for them is a parliament" , "Cheats" , "Fleeces; chessmen" , "men on the board" .)