"Z zawodu jestem lekarzem."

Translation: I am a doctor by profession.

[MATANPEER]

Does the "z" mean "by"?

[Jellei]

No, it mostly means "from" (check here for other meanings). That's just one of the numerous examples when Polish uses a totally different preposition than English.

[MATANPEER]

Thank you. If I understand correctly, you basically say: "I am a doctor from profession". That can make sense if I think about it :)

[JohannesRo397749]

I wrote "by profession I am physician", which may be a bit unusual but I think it is still correct, so it should not be an error.

[Jellei]

Added "physician", such a construction is accepted, but you need "a". But there was a report like that, so maybe it was yours and you just missed 'a' writing the comment.