folly

American  

[fol-ee] / ˈfɒl i /

noun

plural

follies

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.

   Synonyms:

   lunacy, madness, injudiciousness, indiscretion, foolishness, mistake, rashness, imprudence

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.

5. follies, a theatrical revue.

6. Obsolete. wickedness; wantonness.

---

folly British  

/ ˈfɒlɪ /

noun

1. the state or quality of being foolish; stupidity; rashness

2. a foolish action, mistake, idea, etc

3. a building in the form of a castle, temple, etc, built to satisfy a fancy or conceit, often of an eccentric kind

4. (plural) theatre an elaborately costumed revue

5. archaic

   1. evil; wickedness

   2. lewdness; wantonness

---

Usage

What does folly mean? A folly is a foolish action. Follies can refer to various unwise practices, buildings with a purely ornamental purpose, or cabaret-style theatrical revues featuring lots of beautiful, dancing women.

Other Word Forms

• superfolly noun

Etymology

Origin of folly

First recorded in 1175–1225; Middle English folie, from Old French, derivative of fol, fou “foolish, mad”; equivalent to fool ¹ + -y ³ ( def. )

Example Sentences

Yet, “Pretty Lethal” is packed with run-don’t-walk folly that demands to be seen to be believed — if only to throw up your hands and say, “I guess!”

From Salon • Mar. 29, 2026

Gomez added that while attempts to pull licenses border on folly, Carr’s threats and attacks on the media can create a chilling effect and erode the public’s confidence in the press.

From Los Angeles Times • Mar. 16, 2026

Though his acidic sense of humour -- criticised as condescending by some -- is evident throughout, Parr's 180 photographs also amount to a portrait of human folly and environmental destruction.

From Barron's • Jan. 30, 2026

It would be folly not to look at the opportunity cost of taking that $45,000 from your IRA.

From MarketWatch • Jan. 9, 2026

Faced with the obvious folly of his original ambition, to walk five hundred miles to tidewater, he reconsidered his plans.

From "Into the Wild" by Jon Krakauer

Related Words

• absurdity
• craziness
• foolishness
• idiocy
• indiscretion
• lunacy
• madness
• recklessness
• silliness
• stupidity