sadist

A sadist is someone who enjoys inflicting pain on others, sometimes in a sexual sense. Sadists like seeing other people hurt.

A sadist is the opposite of a masochist, who enjoys being in pain. A sadist is all about hurting others, usually to get off sexually. However, this word is about more than sex. Anyone who is mean and enjoys it — like a bully — could be considered a sadist. Anyone who tortures another human being is almost certainly a sadist. Unfortunately, we can all be a sadist at certain moments. If you've ever been mean to someone and enjoyed it, you were being a little sadistic.

Definitions of sadist
1

n someone who obtains pleasure from inflicting pain or others

Antonyms:
masochist
someone who obtains pleasure from receiving punishment
Type of:
degenerate, deviant, deviate, pervert
a person whose behavior deviates from what is acceptable especially in sexual behavior