kingdom Fungi vs fungus kingdom

kingdom Fungi and fungus kingdom both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingdom Fungi	Yes	No	No	No
fungus kingdom	Yes	No	No	No

As nouns, kingdom Fungi and fungus kingdom are synonyms defined as:

kingdom Fungi and fungus kingdom: the taxonomic kingdom including yeast, molds, smuts, mushrooms, and toadstools; distinct from the green plants

Other synonyms of kingdom Fungi include Fungi.

kingdom Fungi (noun)	fungus kingdom (noun)
the taxonomic kingdom including yeast, molds, smuts, mushrooms, and toadstools; distinct from the green plants	the taxonomic kingdom including yeast, molds, smuts, mushrooms, and toadstools; distinct from the green plants