critter vs brute

critter and brute both are nouns.

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

As nouns, brute is a hypernym of critter; that is, brute is a word with a broader meaning than critter:

Other hypernyms of critter include animal, animate being, beast, creature, fauna.

critter (noun)	brute (noun)
a regional term for `creature' (especially for domestic animals)	a living organism characterized by voluntary movement
	a cruelly rapacious person

critter (adjective)	brute (adjective)
	resembling a beast; showing lack of human sensibility