carnivore vs placental mammal

carnivore and placental mammal both are nouns.

Word	Noun	Adjective	Verb	Adverb
carnivore	Yes	No	No	No
placental mammal	Yes	No	No	No

As nouns, placental mammal is a hypernym of carnivore; that is, placental mammal is a word with a broader meaning than carnivore:

carnivore: a terrestrial or aquatic flesh-eating mammal
placental mammal: mammals having a placenta; all mammals except monotremes and marsupials

Other hypernyms of carnivore include eutherian, eutherian mammal, placental.

carnivore (noun)	placental mammal (noun)
a terrestrial or aquatic flesh-eating mammal	mammals having a placenta; all mammals except monotremes and marsupials
any animal that feeds on flesh