What does folly mean?
Folly denotes a lack of good sense, or more concretely, a foolish act, decision, or course of action — one that appears unwise either in hindsight or to any reasonable observer. The word carries a distinctly negative connotation, implying that the mistake was avoidable and often self-indulgent rather than simply unfortunate. In a second, well-established sense, a folly is an expensive ornamental building with no practical purpose, such as a mock ruined abbey or a decorative tower erected in a landscaped park; these flourished among the eighteenth- and nineteenth-century European aristocracy. Both senses share a core idea: resources or effort spent on something ultimately pointless. Folly is somewhat formal or literary in register, appearing frequently in political commentary, history, and criticism (as in Barbara Tuchman's study The March of Folly). Its plural, follies, can describe repeated acts of poor judgment or, historically, light theatrical revues. Related forms are rare, making folly a compact but expressive term for imprudence in both thought and architecture.
nounA foolish act, idea, or practice; lack of good sense. The word also denotes a costly ornamental building with no practical purpose, typically built in a garden or park.
- A foolish act, plan, or undertaking; lack of good sense or judgment.
- A costly but frivolous building, often a decorative structure such as a mock ruin or tower erected in a garden or park.
- (Archaic) Evil or wicked behaviour; lewdness.
"Buying the yacht without consulting his wife turned out to be an expensive folly."
"It would be sheer folly to sign the contract without reading it first."
"Atop the hill stands an eighteenth-century folly, a sham castle built purely for ornament."
The plural follies is standard; it commonly refers to multiple acts of foolishness or, collectively, to ornamental buildings of this kind. It also historically named a genre of lighthearted American theatrical revues.
"The report catalogued the administration's follies over four turbulent years."
The word for human foolishness also names those grand fake ruins aristocrats built in their gardens — monuments to having more money than sense.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of folly
Folly entered English in the Middle Ages, borrowed from Old French folie, meaning madness, foolishness, or wickedness, which itself derives from Latin follem (later follis), originally a bellows or leather bag and later applied to the wind-filled cheeks of a mad or jesting person. The same Latin root gives English words such as foliate and portfolio, whose shared origin lies in the notion of a bag or leaf-shaped container. The architectural sense of folly developed much later, becoming established in the eighteenth century alongside the fashion for ornamental garden buildings.
Related word forms
How folly is actually used
Folly is a slightly formal or literary word; it carries a strong negative connotation of avoidable, often self-inflicted mistakes. In British usage especially, it is firmly established as a term for decorative garden buildings.
Easily confused with folly
"Fully" means completely or entirely, while "folly" means foolishness — the two merely share a similar sound.