critter vs creature

critter and creature both are nouns.

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

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

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

critter (noun)	creature (noun)
a regional term for `creature' (especially for domestic animals)	a living organism characterized by voluntary movement
	a living being
	a person who is controlled by others and is used to perform unpleasant or dishonest tasks for someone else