What are a couple of characteristics of the Monk that indicate that he may not be a devout member of the church and what deadly sin might he represent?

The Monk isn't very pious. He wears fancy clothes and is concerned with worldly pleasures like hunting and eating.  Chaucer describes as a "monk out of his cloister" who is not "worth an oyster". The Monk routinely squanders money that is meant for the poor.