Persecute (7)
I believe the answer is:
oppress
'persecute' is the definition.
(I know that persecute can be written as oppress)
This is all the clue.
(Other definitions for oppress that I've seen before include "Keep in subjection and hardship" , "'Persecute, come down heavy on (7)'" , "Govern harshly, weigh down with care" , "Govern cruelly" , "Treat harshly" .)