i Register
In some senses, barkeep is marked as informal. Watch for register when choosing this word.
noun
A bartender.
I sez to the barkeep' o' the hotel, "Show me the biggest doctor here."
Barkeep, a couple of beers here, please?
verb
To bartend; to keep a bar; to act as a barkeep.
I barkeeped in Pontiac, Michigan and, later in Detroit and Ypsilanti.