mixologist vs barkeeper

mixologist and barkeeper both are nouns.

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

As nouns, mixologist and barkeeper are synonyms defined as:

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

Other synonyms of mixologist include barkeep, bartender.

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