Wow! I just unthinkingly wrote “ο αφεντικό”. I guess I thought a profession must either use a masculine or a feminine article. I didn’t remember that nouns ending in -o are always neuter. But isn’t it strange that a profession can be neuter? I didn’t make a mistake with “το μοντέλο” because a model is a thing primarily and a profession by extension.
Sounds like the modern turkish word Effendi. Wiki tells me it is, and is derived from byzantine Greek: αφέντης. In Persian and Ottoman Turkish language: افندي Efendi, in Arabic: أفندي, Afandī; inPersian: افندی (Afghani), "Afandi") is a title of nobility meaning a Lord or Master.