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

"It was folly, pure folly," protested Lingard, "and this poor fellow has paid for it."

—Joseph Conrad

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.

5

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

Synonyms of folly

• insanity
• absurdity
• idiocy
• 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

But his avuncular encouragement of Tony in what could be absolute folly brings real heart to this section — until calamity intrudes. — David Rooney, HollywoodReporter, 29 July 2026

Modi’s shock demonetization in India in 2016, which wiped out 86% of India’s currency overnight, was pure Big Player folly. — Steve H. Hanke, Fortune, 27 July 2026

The Bloomsbury Group, the 20th-century group of writers and painters renowned for rejecting strict Victorian conventions, is prime example of this; their home, a haven of mismatched color, prints, and folly tucked into every room. — Alex Eagle, Vogue, 26 July 2026

The wall is a folly, in both the architectural and regular sense of the word. — Matt Seaton, The Atlantic, 19 July 2026

Word History

Etymology

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

First Known Use

13th century, in the meaning defined at sense 1

Rhymes for folly

• colley
• collie
• dolly
• golly
• holly
• jolley
• jolly
• lolly
• mollie
• molly
• ollie
• polly

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