folly: Meaning and Definition of

fol•ly

1. 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. a whimsical or extravagant structure built to serve as a conversation piece, lend interest to a view, commemorate a person or event, etc.: found esp. in England in the 18th century.
5. a theatrical revue.
6. wickedness; wantonness.