loose smut vs smut fungus

loose smut and smut fungus both are nouns.

Word	Noun	Adjective	Verb	Adverb
loose smut	Yes	No	No	No
smut fungus	Yes	No	No	No

As nouns, smut fungus is a hypernym of loose smut; that is, smut fungus is a word with a broader meaning than loose smut:

loose smut: a smut fungus of the genus Ustilago causing a smut disease of grains in which the entire head is transformed into a dusty mass of spores
smut fungus: any fungus of the order Ustilaginales

Other hypernyms of loose smut include smut.

loose smut (noun)	smut fungus (noun)
a smut fungus of the genus Ustilago causing a smut disease of grains in which the entire head is transformed into a dusty mass of spores	any fungus of the order Ustilaginales
disease of grains; the entire head is a dusty mass of spores