packman vs seller

packman and seller both are nouns.

Word	Noun	Adjective	Verb	Adverb
packman	Yes	No	No	No
seller	Yes	No	No	No

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

packman: someone who travels about selling his wares (as on the streets or at carnivals)
seller: someone who promotes or exchanges goods or services for money

Other hypernyms of packman include marketer, trafficker, vender, vendor.

packman (noun)	seller (noun)
someone who travels about selling his wares (as on the streets or at carnivals)	someone who promotes or exchanges goods or services for money