Cheat on exclusive gaming device (7)
I believe the answer is:
console
'gaming device' is the definition.
(I've seen this in another clue)
'cheat on exclusive' is the wordplay.
'cheat' becomes 'con' (conning is a kind of cheating).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'exclusive' becomes 'sole' (synonyms).
'con'+'sole'='CONSOLE'
(Other definitions for console that I've seen before include "stops may be arranged here" , "Comfort - control unit" , "Comfort - control panel" , "Key-desk of an organ" , "give reassurance" .)