goose vs brant

goose and brant both are nouns.

Word	Noun	Adjective	Verb	Adverb
goose	Yes	No	Yes	No
brant	Yes	No	No	No

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

goose: web-footed long-necked typically gregarious migratory aquatic birds usually larger and less aquatic than ducks
brant: small dark geese that breed in the north and migrate southward

goose (noun)	brant (noun)
web-footed long-necked typically gregarious migratory aquatic birds usually larger and less aquatic than ducks	small dark geese that breed in the north and migrate southward
flesh of a goose (domestic or wild)
a man who is a stupid incompetent fool