muffin man vs pitchman

muffin man and pitchman both are nouns.

Word	Noun	Adjective	Verb	Adverb
muffin man	Yes	No	No	No
pitchman	Yes	No	No	No

As nouns, pitchman is a hypernym of muffin man; that is, pitchman is a word with a broader meaning than muffin man:

muffin man: formerly an itinerant peddler of muffins
pitchman: someone who travels about selling his wares (as on the streets or at carnivals)

Other hypernyms of muffin man include hawker, packman, peddler, pedlar.

muffin man (noun)	pitchman (noun)
formerly an itinerant peddler of muffins	someone who travels about selling his wares (as on the streets or at carnivals)
	an aggressive salesman who uses a fast line of talk to sell something