Compensate leaders of really evil masterstroke (6)
I believe the answer is:
recoup
'compensate' is the definition.
(I know that recoup is a more specific form of compensate)
'leaders of really evil masterstroke' is the wordplay.
'leaders of' suggests taking the first letters.
'masterstroke' becomes 'coup' (I've seen this in another clue).
The initial letters of 'really evil' is 're'.
're'+'coup'='RECOUP'
(Other definitions for recoup that I've seen before include "Get back or recover - say losses" , "recover money" , "Reimburse or compensate" , "Recover, losses perhaps" , "Get back, say expenses" .)