slaughter vs massacre

slaughter and massacre both are nouns.

Word	Noun	Adjective	Verb	Adverb
slaughter	Yes	No	Yes	No
massacre	Yes	No	Yes	No

As nouns, slaughter and massacre are synonyms defined as:

Other synonyms of slaughter include butchery, carnage, mass murder.

As verbs, slaughter and massacre are synonyms defined as:

Other synonyms of slaughter include mow down.

slaughter (noun)	massacre (noun)
the killing of animals (as for food)	the savage and excessive killing of many people
the savage and excessive killing of many people
a sound defeat

slaughter (verb)	massacre (verb)
kill a large number of people indiscriminately	kill a large number of people indiscriminately
kill (animals) usually for food consumption