The Pardoner in Chaucer's The Canterbury Tales is honest to his immediate listeners (the other travelers), and dishonest and hypocritical to his usual listeners (the people he usually preaches to when he makes his money).
He tells the travelers that he always uses the same tale that he tells them, to fool his usual gullible listeners so they will give him offerings. That's how he earns his living. He is very straightforward with his immediate audience. He does not hide his motives when speaking to the travelers.
But, as he tells the travelers, when he uses the story to preach he uses it to hammer home the point that greed is the root of all evil, therefore they should give their money away--to him. He pretends to be a man of God and to offer forgiveness of sins and salvation, but he really is just greedy himself, and is out to make money. This makes him hypocritical.
Of course, this irony makes "The Pardoner's Tale," as well as other writings in The Canterbury Tales, the high quality that they are--or at least the irony is one of the characteristics that does so. Without it, the story the Pardoner tells would be just another church-related allegory.
In my opinion, the Pardoner is really very hypocritical. Chaucer seems to see all of the clergy (except the parson) as hypocrites who do not really care about people.
The Pardoner says that he always preaches his sermons on the idea that the love of money is the root of all evil. He expounds on this idea so as to make the people buy pardons from him. But he also tells us that he really doesn't care about the people. All he wants to do is get money. He is willing to manipulate people in any way he can so as to get their money.
This seems hypocritical to me because he is supposed to care about people's souls and because he is doing exactly what he preaches against.