Delighting in or feeling pleasure from the pain or humiliation of others. / Of behaviour which gives pleasure in the pain or humiliation of others.

In a sadistic manner. / In a particularly horrible or brutal manner, as painfully as possible.

One who derives pleasure through cruelty or pain to others.

plural of sadist

plural of sadistic personality disorder

(historical, psychiatry) A disorder characterized by cruel, aggressive, demeaning, and manipulative behavior towards others.