A guimpe is a garment worn by women during the Middle Ages. Where on the body would a guimpe be worn?

Neck and shoulders.

The guimpe (from the French guimpe), or chemisette, was a garment which developed in medieval Western Europe. It was a silk or linen kerchief, sometimes sheer, sometimes starched, which covered the neck and shoulders of the wearer.

It was worn as part of the garb of a woman of means, both to show social standing —due to the added upkeep it required, and to demonstrate the woman's sense of modesty. As women in Renaissance Italy began to leave their heads uncovered, and to expose their shoulders, the guimpe slowly fell into disuse.

Its use continued solely in monasteries, as part of a nun's religious habit, where it would be worn together with a coif and wimplet. As women's religious orders began to adopt contemporary attire, it has largely disappeared from these circles as well.