Sadistic (adjective)

1. Deriving pleasure from inflicting pain, suffering, or humiliation on others.
2. Characterized by or showing an inclination for sadism.

Origin:

Early 19th century: from french sadique, from the name of the marquis de sade (1740–1814), french nobleman and writer whose works describe brutal and abnormal sexual practices.

Examples:

1. He had a sadistic streak, enjoying the thought of causing others pain.
2. The sadistic torture methods used by the prison guards were exposed in a government investigation.
3. The sadistic serial killer was known for his brutal methods of killing and mutilation.
4. Some people have a sadistic streak and enjoy seeing others suffer.
5. The sadistic punishments inflicted on prisoners were inhumane and unacceptable.