barkeeper vs bartender

barkeeper and bartender both are nouns.

Word	Noun	Adjective	Verb	Adverb
barkeeper	Yes	No	No	No
bartender	Yes	No	No	No

As nouns, barkeeper and bartender are synonyms defined as:

barkeeper and bartender: an employee who mixes and serves alcoholic drinks at a bar

Other synonyms of barkeeper include barkeep, mixologist.

barkeeper (noun)	bartender (noun)
an employee who mixes and serves alcoholic drinks at a bar	an employee who mixes and serves alcoholic drinks at a bar