The question of whether Tartuffe is an ignorant man is easily answered with a simple "no". Tartuffe was, in fact, a very astute and cunning man who was able to extrapolate the traits of the people with whom he established contact. He was a master at using these traits to decide which were weak and which were strong. As a result, he used the ingenuousness and naivete, or other weaknesses, of individuals to benefit himself.
As to whether he was a charlatan or not, one must consider what a charlatan actually does: A charlatan lies, cons, and deceives. This being said, we could conclude that Tartuffe somewhat reunites the qualities of a charlatan. He was indeed a hypocrite, and a hoax. He deceived, and lied openly to people, and had no shame in doing so. As far as that goes, one can say that he is indeed the poster boy for charlatans.
Yet, not all charlatans are witty, analytical, nor well-organized in their plan of actions as to how to con people. Not all of them are as powerful, either. Therefore, one can conclude that Tartuffe did the basic actions of a charlatan, however, he did it with the preciseness, the care, and the detail that only a very street-wise witty person can do. Ignorant? He is not. A charlatan? He is: A so-to-speak "upgraded" form of a charlatan.