costume vs fursuit

costume and fursuit both are nouns.

Word	Noun	Adjective	Verb	Adverb
costume	Yes	No	Yes	No
fursuit	Yes	No	No	No

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

Other hyponyms of costume include fancy dress, masquerade, masquerade costume.

costume (noun)	fursuit (noun)
the attire worn in a play or at a fancy dress ball	A full body animal suit
the attire characteristic of a country or a time or a social class
unusual or period attire not characteristic of or appropriate to the time and place
the prevalent fashion of dress (including accessories and hair style as well as garments)

costume (verb)	fursuit (verb)
dress in a costume
furnish with costumes; as for a film or play