beastly vs brute

beastly is not a noun while brute is a noun.

Word	Noun	Adjective	Verb	Adverb
beastly	No	Yes	No	Yes
brute	Yes	Yes	No	No

As adjectives, beastly and brute are synonyms defined as:

beastly and brute: resembling a beast; showing lack of human sensibility

Other synonyms of beastly include bestial, brutal, brutish.

beastly (noun)	brute (noun)
	a living organism characterized by voluntary movement
	a cruelly rapacious person

beastly (adjective)	brute (adjective)
resembling a beast; showing lack of human sensibility	resembling a beast; showing lack of human sensibility
(informal) very unpleasant

beastly (adverb)	brute (adverb)
in a beastly manner