Ecclesiastic is a person inside a religious order. The adjective, on other other hand, is ecclesiastical.
Two centuries after Olaus Magnus, another ecclesiastic, the Danish missionary Hans Egede (who eventually became the bishop of Greenland), visited that icy island early in the eighteenth century, in hope of converting the natives to Christianity. (NY Times)
Rome’s ecclesiastical tailors are seeing red these days, but they’re not complaining. (USA Today)
Is this from the book title of the same name?