To revert back into a condition of cruelty and brutality: Following the war, the country was rebarbarized into a state of havoc, savagery, ruthlessness, and viciousness.

Rare, the process of returning something or a person back into a state of wildness and brutality: Rebarbarizing was part of the hooligans plan for changing the ways of new members into ruthless, remorseless, and merciless people.