beast vs assaulter

beast and assaulter both are nouns.

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

As nouns, assaulter is a hypernym of beast; that is, assaulter is a word with a broader meaning than beast:

Other hypernyms of beast include aggressor, assailant, attacker.

beast (noun)	assaulter (noun)
a living organism characterized by voluntary movement	someone who attacks
a cruelly rapacious person