cheap-jack vs seller

cheap-jack and seller both are nouns.

Word	Noun	Adjective	Verb	Adverb
cheap-jack	Yes	No	No	No
seller	Yes	No	No	No

As nouns, seller is a hypernym of cheap-jack; that is, seller is a word with a broader meaning than cheap-jack:

Other hypernyms of cheap-jack include marketer, trafficker, vender, vendor.

cheap-jack (noun)	seller (noun)
a seller of shoddy goods	someone who promotes or exchanges goods or services for money