Show mode off (4)
I believe the answer is:
demo
'show' is the definition.
(I've seen this in another clue)
'mode off' is the wordplay.
'off' indicates anagramming the letters.
'mode' is an anagram of 'DEMO'.
(Other definitions for demo that I've seen before include "Tape sent to recording studio" , "March (abbr)" , "Protest march (sl.)" , "Protest (abbr)" , "exhibit" .)