fratricide vs murderer

fratricide and murderer both are nouns.

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

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

fratricide: a person who murders their brother or sister
murderer: a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)

Other hypernyms of fratricide include liquidator, manslayer.

fratricide (noun)	murderer (noun)
the murder of your sibling	a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)
fire that injures or kills an ally
a person who murders their brother or sister