noun
lust killer; lust murderer
Refers to a person who commits murder for sexual pleasure. A formal or criminological term.
快楽殺人者は、被害者を苦しめることに性的興奮を覚えるとされる。
Lust killers are said to derive sexual excitement from inflicting suffering on their victims.
シリアルキラー is a broader term for a serial killer, not necessarily motivated by sexual pleasure. 快楽殺人者 specifically emphasizes the lust-driven motive.
Compound of 快楽 (かいらく, 'pleasure') + 殺人者 (さつじんしゃ, 'murderer').