crazy weed vs leguminous plant

crazy weed and leguminous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
crazy weed	Yes	No	No	No
leguminous plant	Yes	No	No	No

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

crazy weed: any of several leguminous plants of western North America causing locoism in livestock
leguminous plant: an erect or climbing bean or pea plant of the family Leguminosae

Other hypernyms of crazy weed include legume.

crazy weed (noun)	leguminous plant (noun)
any of several leguminous plants of western North America causing locoism in livestock	an erect or climbing bean or pea plant of the family Leguminosae