dealer vs peddler

dealer and peddler both are nouns.

Word	Noun	Adjective	Verb	Adverb
dealer	Yes	No	No	No
peddler	Yes	No	No	No

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

Other hyponyms of dealer include drug dealer, drug peddler, drug trafficker, pusher.

dealer (noun)	peddler (noun)
a firm engaged in trading	someone who travels about selling his wares (as on the streets or at carnivals)
a seller of illicit goods	an unlicensed dealer in illegal drugs
the person who distributes the playing cards in a card game
someone who purchases and maintains an inventory of goods to be sold
the major party to a financial transaction at a stock exchange; buys and sells for his own account