How to say "murderer" in Japanese

Choosing the right word

殺しころしCommon
nounChiefly denotes the act of killing or murder rather than the person, fitting talk of the deed itself; its 'murderer' sense is marginal, so this is seldom the word you want for a killer.
一度いちど殺ころすと、殺ころしが楽たのしくなる。↗
Once we've killed, we enjoy killing.
人殺しひとごろしCommon
nounRefers to a murderer — the person who kills — with strong condemnatory force; it is often hurled at someone as an accusation, and can also denote the deed itself.
彼かれは、人殺ひとごろしも同然どうぜんだ。↗
He is no better than a murderer.

Use 「人殺し」 for the person — a killer condemned for the deed; 「殺し」 chiefly names the act of killing or murder, and its 'murderer' sense is marginal.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

Japanese equivalents

Say it right, write it right