cutthroat vs murderer

cutthroat and murderer both are nouns.

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

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

cutthroat: someone who murders by cutting the victim's throat
murderer: a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)

Other hypernyms of cutthroat include liquidator, manslayer.

cutthroat (noun)	murderer (noun)
someone who murders by cutting the victim's throat	a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)

cutthroat (adjective)	murderer (adjective)
ruthless in competition