giving or receiving of pleasure from acts involving the receipt or infliction of pain or humiliation

Sadomasochism is a word which is mostly used in a social (non-medical) way. It means that people get together to either give or receive pain and humiliation. Usually it's a form of sex play.

Picture from Aline et Valcour (1795) by De Sade. The caption reads Is heaven just when it abandons virtue to so big a torment..?

Sadists enjoy inflicting pain on others or humiliating them. Masochists get pleasure from being tortured, hurt, or humiliated.