Repudiate, cast off (6)
I believe the answer is:
disown
I believe this clue is a double definition.
'repudiate' is the first definition.
(I've seen this in another clue)
'cast off' is the second definition.
(I've seen this in another clue)
(Other definitions for disown that I've seen before include "Refuse responsibility for" , "Repudiate, disclaim" , "Reject all connection with, refuse to acknowledge" , "Refuse to be connected with" , "Disclaim or deny" .)