Definition of "folie" [folie]

• A Middle English form of folly. (noun)

The Century Dictionary (Public Domain)

• "Le Grande du Saulle has given to the disease in which there is a morbid doubt about everything done, the name folie de doute."
• "It might be read as another sign of the phenomenon I am calling folie à deux or codependency of marriage."
• "They addressed friends and colleagues from behind electronic walls of accusatory e-mails and confrontational blog posts, and their storybook devotion to each other slowly warped into a shared madness — what is known as a folie à deux."