I must transform endless insolence into incentives (7)
I believe the answer is:
stimuli
'incentives' is the definition.
(I've seen this before)
'i must transform endless insolence' is the wordplay.
'transform' indicates anagramming the letters.
'endless' means to remove the last letter.
'insolence' becomes 'lip' (I've seen this in another clue).
'lip' with its last letter taken off is 'li'.
'i'+'must'='imust'
'imust' with letters rearranged gives 'stimu'.
'stimu'+'li'='STIMULI'
'into' is the link.
(Other definitions for stimuli that I've seen before include "Things that provoke reactions" , "Promoters of activity" , "Things promoting activity" , "they provoked reaction" , "Things provoking reactions" .)