marsupial vs metatherian

marsupial and metatherian both are nouns.

Word	Noun	Adjective	Verb	Adverb
marsupial	Yes	Yes	No	No
metatherian	Yes	No	No	No

As nouns, metatherian is a hypernym of marsupial; that is, metatherian is a word with a broader meaning than marsupial:

marsupial: mammals of which the females have a pouch (the marsupium) containing the teats where the young are fed and carried
metatherian: primitive pouched mammals found mainly in Australia and the Americas

marsupial (noun)	metatherian (noun)
mammals of which the females have a pouch (the marsupium) containing the teats where the young are fed and carried	primitive pouched mammals found mainly in Australia and the Americas

marsupial (adjective)	metatherian (adjective)
of or relating to the marsupials