Leave a note to provoke (4)
I believe the answer is:
goad
'to provoke' is the definition.
(goading is a kind of provoking)
'leave a note' is the wordplay.
'leave' becomes 'go' (to go is to depart or leave).
'note' becomes 'd' (musical note).
'go'+'a'+'d'='GOAD'
(Other definitions for goad that I've seen before include "that provides motivation" , "Provoke, spur" , "Cattle prod" , "Spur or stimulate" , "Spur, urge on" .)