murderer vs malefactor

murderer and malefactor both are nouns.

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

As nouns, malefactor is a hypernym of murderer; that is, malefactor is a word with a broader meaning than murderer:

murderer: a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)
malefactor: someone who has committed a crime or has been legally convicted of a crime

Other hypernyms of murderer include criminal, crook, felon, outlaw, killer, slayer.

murderer (noun)	malefactor (noun)
a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)	someone who has committed a crime or has been legally convicted of a crime