In the "General Prologue" to The Canterbury Tales, Geoffrey Chaucer describes Hubert the Friar as friendly and jovial, pleasure-loving but dignified, a compassionate confessor, and one of the best at begging alms to help the poor. He is friendly, well-spoken, adept at debate, well-dressed, an excellent musician and singer, and not above joining with common folk in a little gossip now and then.

Chaucer's seemingly benign if not glowing description of the Friar actually hides biting criticism. The common folk with whom the Friar associated actually turn out to be wealthy landowners and noblewomen as well as tavern owners from the towns he visited, in addition to every barmaid in every tavern (given his propensity towards lechery).

The Friar's rationale in associating with the rich rather than with the poor—who he is supposed to comfort and help support—is that there is no money to be made by associating with poor people. The light penances he gave at confession were paid for by the repentant souls he counseled. The alms that the Friar collected for the poor ended up in his own pocket and on his own back (by way of his fine clothing).

In all, the Friar did not behave in a way befitting his station as a poor, humble scholarly friar:

In this he was not like a cloisterer,
With threadbare cope like the poor scholar,
But he was like a lord or like a pope. (261–263)

What are the main characteristics of the friar in The Canterbury Tales?

Like the Prioress and the Monk before him, the Friar is another representative of the religious establishment who fails to any of the expected virtues.  Among other things,

He hadde madd full many a marriage/Of younge wommen at his owene cost. (ll.212-213)

[He arranged many young women's marriage at his own expense.]

He may sound like a generous man, but Chaucer implies that the Friar arranges these marriages because the "younge wommen" are his mistresses and, more to the point, pregnant.  

Even worse than his illicit affairs, however, is that, as a person licensed th hear confessions:

He heard confessions pleasantly,/And his absolutions were easy;/The penance he required was light/When he knew there was going to be a good payment [to him]. (ll. 221-225)

The Friar's "selling" of forgiveness is one of the most serious sins the Friar could commit because he is subverting an important religious event--the confession of sin and God's forgiveness.  Because God's forgiveness is supposed to be freely given, as long as the confession is sincere, injecting money into this ceremony negates its true value completely.  Later, we learn that although the Friar knows tavern keepers very well, he has no acquaintance with the poor and the sick, another serious example of the Friar's failings as a representative of the Church.

In sum, then, the Friar is depicted as a religious man in name only, a person who does nothing but corrupt his own church for private gain and, in the process, destroys the foundations of faith among the people he is supposed to serve.  Chaucer's portrait of the Friar is one of the harshest views of religious corruption in The Canterbury Tales.