barkeep vs barkeeper

barkeep and barkeeper both are nouns.

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

As nouns, barkeep and barkeeper are synonyms defined as:

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

Other synonyms of barkeep include bartender, mixologist.

barkeep (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