noun
folly
FO-lee
noun
1
A foolish act or belief, especially one with serious or costly consequences.
"Investing his entire savings in one stock was pure folly."
"History remembers the war as a tragic folly."
2
An elaborate, purely decorative building constructed for visual effect rather than practical use.
"The estate had a stone folly built to look like a ruined tower."
How to Use Folly
Learner’s notesIn plain EnglishA foolish, often costly mistake, or a purely decorative building built just for looks.
Common pairings
sheer folly
act of folly
a garden folly
Word Forms
follied past tense, follies plural, follies plural, follies singular
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Etymology
From Old French folie ("madness"), from the adjective fol ("mad, foolish") — the same root that gives us "fool."