All 3 Uses of

provincial
in
Candide

A sergeant told them they must wait, that the Commandant could not speak to them, and that the reverend Father Provincial does not suffer any Spaniard to open his mouth but in his presence, or to stay above three hours in the province.†
Chpt 14

As they were Germans, they sat a good while at table, waiting for the reverend Father Provincial, and the Commandant spoke to his dear Candide as follows.†
Chpt 14 *

Definitions:

(1) (provincial as in: provincial attitude)
unsophisticated (meant disapprovingly to refer to old-fashioned or narrow-minded attitudes and ideas)
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Provincial can also mean "related to a province" or "related to the provinces." Its more literary meaning of unsophisticated originated as a pejorative term for ideas held in the provinces that were considered old-fashioned or uninformed by many who lived in the capital city.