Not very positively, I'm afraid. Chaucer only wholly approves of the Knight, the Parson, and the Plowman in his Prologue.
The monk wears fine clothing and disregards the oath of the holy life he has pledged himself to living. He is more concerned with worldly things like hunting and eating and dressing well. In fact, Chaucer calls him a "monk out of his cloister" who is not "worth an oyster".
The monk keeps nice horses and fancy greyhounds for hunting purposes. He dresses extremely well and is very fat. In other words, he lives more richly than a holy man should, he squanders money that the poor could be using by supporting animals, and eats more than is necessary to keep himself alive and healthy.