adzuki bean vs leguminous plant

adzuki bean and leguminous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
adzuki bean	Yes	No	No	No
leguminous plant	Yes	No	No	No

As nouns, leguminous plant is a hypernym of adzuki bean; that is, leguminous plant is a word with a broader meaning than adzuki bean:

adzuki bean: bushy annual widely grown in China and Japan for the flour made from its seeds
leguminous plant: an erect or climbing bean or pea plant of the family Leguminosae

Other hypernyms of adzuki bean include legume.

adzuki bean (noun)	leguminous plant (noun)
bushy annual widely grown in China and Japan for the flour made from its seeds	an erect or climbing bean or pea plant of the family Leguminosae