Abdicate or disown (8)
I believe the answer is:
renounce
I believe this is a double definition.
'abdicate' is the first definition.
(I know that abdicate is a more specific form of renounce)
'disown' is the second definition.
(I know that disown can be written as renounce)
(Other definitions for renounce that I've seen before include "Foreswear, relinquish" , "Reject, perhaps the devil" , "Publicly give up rights" , "Abdicate or disown" , "Decide to forgo" .)