race murder vs racial extermination

race murder and racial extermination both are nouns.

Word	Noun	Adjective	Verb	Adverb
race murder	Yes	No	No	No
racial extermination	Yes	No	No	No

As nouns, race murder and racial extermination are synonyms defined as:

race murder and racial extermination: systematic killing of a racial or cultural group

Other synonyms of race murder include genocide.

race murder (noun)	racial extermination (noun)
systematic killing of a racial or cultural group	systematic killing of a racial or cultural group