To refuse to acknowledge as one’s own. (Merriam – Webster)
To repudiate any connection or identification with. (Merriam – Webster)
To deny the validity or authority of. (Merriam – Webster)
To make it known that you no longer have any connection with someone that you were closely connected with. (Cambridge Dictionary)
To refuse to acknowledge as belonging or pertaining to oneself; deny the ownership of or responsibility for; repudiate; renounce. (Dictionary.com)
If you disown someone or something, you say or show that you no longer want to have any connection with them or any responsibility for them. (Collins Dictionary)
Twenty two Times Parents Disowned Their Children (And Vice Versa) And Why.
Is it legally possible for a son to disown his own father?