brute vs poikilotherm

brute and poikilotherm both are nouns.

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

As nouns, poikilotherm is a hyponym of brute; that is, poikilotherm is a word with a more specific, narrower meaning than brute:

brute: a living organism characterized by voluntary movement
poikilotherm: an animal whose body temperature varies with the temperature of its surroundings; any animal except birds and mammals

brute (noun)	poikilotherm (noun)
a living organism characterized by voluntary movement	an animal whose body temperature varies with the temperature of its surroundings; any animal except birds and mammals
a cruelly rapacious person

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