sea creature vs brute

sea creature and brute both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea creature	Yes	No	No	No
brute	Yes	Yes	No	No

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

sea creature: any of numerous animals inhabiting the sea including e.g. fishes and molluscs and many mammals
brute: a living organism characterized by voluntary movement

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

sea creature (noun)	brute (noun)
any of numerous animals inhabiting the sea including e.g. fishes and molluscs and many mammals	a living organism characterized by voluntary movement
	a cruelly rapacious person

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