man-on-a-horse vs agaric

man-on-a-horse and agaric both are nouns.

Word	Noun	Adjective	Verb	Adverb
man-on-a-horse	Yes	No	No	No
agaric	Yes	No	No	No

As nouns, agaric is a hypernym of man-on-a-horse; that is, agaric is a word with a broader meaning than man-on-a-horse:

man-on-a-horse: an edible agaric with yellow gills and a viscid yellow cap that has a brownish center
agaric: a saprophytic fungus of the order Agaricales having an umbrellalike cap with gills on the underside

man-on-a-horse (noun)	agaric (noun)
an edible agaric with yellow gills and a viscid yellow cap that has a brownish center	a saprophytic fungus of the order Agaricales having an umbrellalike cap with gills on the underside
	fungus used in the preparation of punk for fuses