beast vs aggressor

beast and aggressor both are nouns.

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

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

Other hypernyms of beast include assailant, assaulter, attacker.

beast (noun)	aggressor (noun)
a living organism characterized by voluntary movement	someone who attacks
a cruelly rapacious person	a confident assertive person who acts as instigator