auctioneer vs broker

auctioneer and broker both are nouns.

Word	Noun	Adjective	Verb	Adverb
auctioneer	Yes	No	Yes	No
broker	Yes	No	Yes	No

As nouns, broker is a hypernym of auctioneer; that is, broker is a word with a broader meaning than auctioneer:

auctioneer: an agent who conducts an auction
broker: a businessman who buys or sells for another in exchange for a commission

Other hypernyms of auctioneer include agent, factor.

auctioneer (noun)	broker (noun)
an agent who conducts an auction	a businessman who buys or sells for another in exchange for a commission

auctioneer (verb)	broker (verb)
sell at an auction	act as a broker