Coenobite

noun

A man who piously shuts himself up to meditate upon the sin of wickedness; and to keep it fresh in his mind joins a brotherhood of awful examples.

    O Coenobite, O coenobite,
    Monastical gregarian,
    You differ from the anchorite,
    That solitudinarian:
    With vollied prayers you wound Old Nick;
    With dropping shots he makes him sick.

        Quincy Giles


—Ambrose Bierce, The Devil's Dictionary