the state or quality of being foolish; lack of understanding or sense.
2.
a foolish action, practice, idea, etc.; absurdity: the folly of performing without a rehearsal.
3.
a costly and foolish undertaking; unwise investment or expenditure.
4.
Architecture. a whimsical or extravagant structure built to serve as a conversation piece, lend interest to a view, commemorate a person or event, etc.: found especially in England in the 18th century.
a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.
an extraordinary or unusual thing, person, or event; an exceptional example or instance.
a stew of meat, vegetables, potatoes, etc.
a chattering or flighty, light-headed person.
a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
early 13c., from O.Fr. folie, from fol (see fool). Sense of "costly structure considered to have shown folly in the builder" is attested from 1650s. Used since M.E. of place names, especially country estates, as a form of O.Fr. folie in its meaning "delight." Meaning "glamorous