Reject as untrue or unjust (9)
I believe the answer is:
repudiate
'reject as untrue or unjust' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for repudiate that I've seen before include "Refuse to be associated with" , "Give denial" , "Reject or deny as unfounded" , "Denounce" , "Reject and refuse to acknowledge" .)