ferryman vs Charon

ferryman and Charon both are nouns.

Word	Noun	Adjective	Verb	Adverb
ferryman	Yes	No	No	No
Charon	Yes	No	No	No

As nouns, Charon is a hyponym of ferryman; that is, Charon is a word with a more specific, narrower meaning than ferryman:

ferryman: a man who operates a ferry
Charon: (Greek mythology) the ferryman who brought the souls of the dead across the river Styx or the river Acheron to Hades

ferryman (noun)	Charon (noun)
a man who operates a ferry	(Greek mythology) the ferryman who brought the souls of the dead across the river Styx or the river Acheron to Hades