"Tapster" is now obsolete but can be translated as barman or barmaid – whoever is in charge of the "tap".
The Guardian(Sep 19, 2014)
So also are the adventures of “that loose fish the Pardoner” with the tapster Kit at the Chequer Inn.
Power, Eileen, Medieval English Nunneries c. 1275...(2012)
As he proceeds, the youth is joined by the ghost of the tapster, who accompanies him.
Gerould, Gordon Hall, The Grateful Dead—The History of a...(2012)