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

For example, Gramm-Rudman-Hollings, perhaps the most serious attempt to eliminate fiscal follies, promised to gradually reduce federal deficits until 1991, when a balanced budget would be achieved. — Steve H. Hanke, Fortune, 15 July 2026

Adopting the Red Scare tactics of the last century seems unlikely to save Republicans from the political consequences of this folly. — John Cassidy, New Yorker, 13 July 2026

But the most astute recognize the folly of the notion that the military can sidestep politics entirely. — Missy Ryan, The Atlantic, 10 July 2026

At the same time, the three main actors waited through mounting production delays that threatened to sink Spielberg’s folly. — Howard Cohen, Miami Herald, 9 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