beast vs fauna

beast and fauna both are nouns.

Word	Noun	Adjective	Verb	Adverb
beast	Yes	No	No	No
fauna	Yes	No	No	No

As nouns, beast and fauna are synonyms defined as:

Other synonyms of beast include animal, animate being, brute, creature.

beast (noun)	fauna (noun)
a living organism characterized by voluntary movement	a living organism characterized by voluntary movement
a cruelly rapacious person	all the animal life in a particular region or period