A sadomasochist is a person who gets sexual pleasure from hurting someone, or from being hurt, or from both. It is the person-word that sits beside sadomasochism (the practice). Like the longer word, it is adult and rather clinical. Many people never use this noun about themselves; they just say they are “into SM.” Though actually, in ordinary talk the word can sound like an insult even when the careful meaning is only “this is their sexual taste.” That gap between the textbook sense and the way it lands in a conversation is worth noticing. It names the person, not the habit: the habit is sadomasochism.

SM 者；施虐受虐者