Send timer off (5)
I believe the answer is:
remit
'send' is the definition.
(I've seen this before)
'timer off' is the wordplay.
'off' is an anagram indicator.
'timer' is an anagram of 'REMIT'.
(Other definitions for remit that I've seen before include "Pardon or transmit money" , "Task/area assigned (to an organisation)" , "Brief - transfer" , "Pardon (a sin)" , "Shorten sentence or send money" .)