A prioress was the head of a house of nuns; she was below an abbess in rank, but still an important person. This prioress, though supposedly dedicated to the religious life, is depicted as very worldly. For example, we learn that:

Her smile [was] a very simple one and coy.

Coy means shy, but it also carries the connotation of deceptive or flirtatious, as if the prioress is pretending to be shyer than she really is.

She also has table manners that are bit dainty for a person who is supposed to be dedicated to God, suggesting that she puts too much emphasis on outward appearances and courtly behavior:

Of table manners she had learnt it all,

For from her lips she'd let no morsel fall

Nor deeply in her sauce her fingers wet;

She'd lift her food so well she'd never get

A single drop or crumb upon her breast

The prioress wears a shiny golden brooch that says "Amor vincit omnia," which means "love conquers all." This could be a reference to Christian charity, but the context shows that Chaucer is being ironic: the quote is from Virgil, a pagan author. The prioress also shows that her love is misplaced, as she cares more about pampering her lap dogs than about the welfare of other humans. We can see through the details of her outward appearance and behavior—such as her attempts to use French—that Chaucer wishes to convey that she is probably pretentious and less than kind to those beneath her.

Chaucer's portrayal of this supposedly religious woman is ironic: he paints her as a social climber who is more interested in the worldly than the spiritual matters of life. This is part of his critique of corruption in the church during his time period.