This is the 6382nd most frequent Polish word.
bułgar
"Bułgar" in Polish means "Bulgarian" (a person from Bulgaria).
Here, 'Bułgar' is used as a noun denoting an individual from Bulgaria.
Bułgar mieszka w Sofii.
The Bulgarian lives in Sofia.
In this context, 'bułgar' is used as a noun but likely symbolizing something associated with Bulgaria, such as cuisine.
Znam przepis na tradycyjny bułgar.
I know a recipe for a traditional Bulgarian dish.
Here, 'Bułgar' is used as a proper noun referring to the nation or cultural aspects related to Bulgaria.