The Pardoner is a man of ambivalent appearance because he is a somewhat feminine man with thin long blond, waxen hair, hanging "like rat-tails," which suggest slyness. He does not wear his hood as most of the religious order do; instead, he wears a little cap in which he sews a relic. He sells indulgences and, in so doing, he represents the rampant corruption in the medieval Catholic Church.
The Pardoner, who has taken a vow of poverty as one of a religious order, wears a little cap in which he sews a relic, suggesting his religiosity, but, in contrast, he rides in the latest style. In addition to his somewhat contradictory physical appearance, his gender is also uncertain because he can grow no beard:
Smoother than ever chin was left by barber
I judge he was a gelding [neutered stallion], or a mare...
His wallet lay before him on his lap,
Brimful of pardon come from Rome all hot.
He has the same small voice a goat has got.
That the Pardoner puts his wallet on his lap so he can see it suggests that he is avaricious; in contrast, as a man of the cloth he has taken a vow of poverty. Here again he demonstrates his moral corruption.
The Pardoner's voice sounding like a goat also suggests the contradictions and corruption attached to the Pardoner himself because the symbolism of the goat varies from evil to good. For instance, in mythology the goat was the image of the pagan god Pan, who was the god of all things in Crete and Greece. With the advent of Christianity, however, the image of Pan with his cloven hoofs and horns became symbolic of the devil.
The Pardoner's appearance reflects his inner depravity in several ways. He had hair "yellow as wax" that hung "lankly" on is head, "thin and droopy" which reflected his spiritual state: "thin and droopy." He is "disheveled" and his eyes are "shiny" and are compared to a rabbits eyes. Again this reflects his inner state: he is like an animal, not a human. His voice "bleated like a goat." Sinners and those serving Satan are often compared to goats in the Bible and I believe that Chaucer is using a similar comparison to again show the Pardoner's depraved spiritual state. Finally, he had no beard and seemed to be not a true man; but a "gelding or a mare." This again shows his inner state. He is not a man; and has not the spirit, courage, or integrity of a man. Chaucer uses the physical description of the pardoner to draw a picture of one with no true spiritual life and no real connection to the God he claims to serve.