folly

noun

fol·​ly ˈfä-lē 

plural follies

1

: lack of good sense or normal prudence and foresight

his folly in thinking he could not be caught

2

a

: criminally or tragically foolish actions or conduct

b

obsolete : evil, wickedness

especially : lewd behavior

3

: a foolish act or idea

The prank was a youthful folly.

4

: an excessively costly or unprofitable undertaking

Paying so much for that land was folly, since it was all rocks and scrub trees.

5

: an often extravagant picturesque building erected to suit a fanciful taste

Synonyms

• absurdity
• asininity
• bêtise
• fatuity
• foolery
• foppery
• idiocy
• imbecility
• inanity
• insanity
• lunacy
• stupidity

Examples of folly in a Sentence

the folly of driving fast on steep, winding roads

his folly in thinking that he would not be noticed

The folly of such an action should be apparent to everyone.

the follies of the modern world

the famous Ziegfeld Follies of the 1920s

Recent Examples on the Web

The infantile abomination that is The Boss Baby is the most unhinged example of the studio’s manic folly. —James Grebey, Vulture, 31 Jan. 2025

The book’s hero is Will Andrews, an idealistic college student, who gets lured into this folly by an ambitious, fortune-seeking hunter named Miller. —Calum Marsh, New York Times, 22 Jan. 2025

Even the decision to join PSG, which looked to some like folly, made sense through a certain lens. —Jack Lang, The Athletic, 18 Jan. 2025

But, first, how reporting on an architectural folly in Manhattan sparked a love for leaning towers everywhere. —Eric Lach, The New Yorker, 4 Feb. 2025

Word History

Etymology

Middle English folie, from Anglo-French, from fol fool

First Known Use

13th century, in the meaning defined at sense 1

Kids Definition

folly

noun

fol·​ly ˈfäl-ē 

plural follies

1

: lack of good sense or judgment

2

: foolish behavior

3

: a foolish act or idea