chapman vs pitchman

chapman and pitchman both are nouns.

Word	Noun	Adjective	Verb	Adverb
chapman	Yes	No	No	No
pitchman	Yes	No	No	No

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

chapman: archaic term for an itinerant peddler
pitchman: someone who travels about selling his wares (as on the streets or at carnivals)

Other hypernyms of chapman include hawker, packman, peddler, pedlar.

chapman (noun)	pitchman (noun)
archaic term for an itinerant peddler	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