murderer vs manslayer

murderer and manslayer both are nouns.

Word	Noun	Adjective	Verb	Adverb
murderer	Yes	No	No	No
manslayer	Yes	No	No	No

As nouns, murderer and manslayer are synonyms defined as:

murderer and manslayer: a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)

Other synonyms of murderer include liquidator.

murderer (noun)	manslayer (noun)
a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)	a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)