foolishness

foolishness — noun

1. behaviour or thinking that shows poor judgment and a lack of common sense, often

1.nounB1
Definition

behaviour or thinking that shows poor judgment and a lack of common sense, often leading to unwanted results or regret.

Example

The sheer foolishness of hiking in a thunderstorm was obvious to everyone except Roya.

collocation: sheer foolishness

Defne later admitted her foolishness in believing the promises of the online scam.

the foolishness of + gerund

Common collocations
  • sheer foolishness
  • pure foolishness
  • youthful foolishness
  • the foolishness of
Synonyms
  • stupidity

    harsher in tone; suggests low intelligence rather than poor judgment

  • folly

    more formal; often refers to a grand, self-defeating mistake

  • nonsense

    focuses on ideas or speech being pointless rather than behaviour being unwise

Antonyms
  • wisdom

    the ability to make good judgments based on experience

  • good sense

    practical, sound judgment in everyday matters

Grammar Patterns

the foolishness of + noun/gerund

sheer/pure foolishness

Usage Note

Almost always uncountable. Frequently found in the patterns 'the foolishness of + doing something' and 'sheer / pure foolishness'.

Common Mistakes

His foolishness of believing the lie cost him everything.
His foolishness in believing the lie cost him everything.
the standard pattern uses 'foolishness in + gerund', not 'of + gerund'.
She called his plan a stupidity.
She called his plan a piece of foolishness.
'foolishness' is uncountable and cannot take 'a' alone in this sense.

2. something that a person does or says that is not sensible, often causing embarra

2.nounB1
Definition

something that a person does or says that is not sensible, often causing embarrassment, annoyance, or minor trouble.

Example

Valentina laughed off her late-night online shopping as a harmless youthful foolishness.

countable: a + foolishness

The CEO described the failed merger as the worst business foolishness he had ever seen.

Common collocations
  • youthful foolishness
  • silly foolishness
  • minor foolishness
  • business foolishness
Synonyms
  • mistake

    neutral; implies an error without the same judgemental tone

  • silliness

    lighter in tone; suggests harmless fun rather than poor judgment

  • blunder

    more serious; a careless or embarrassing mistake

Antonyms

Grammar Patterns

a foolishness

countable: plural -es

Usage Note

Countable use (a foolishness / foolishnesses) is less common than uncountable. It typically refers to a single specific act or remark that the speaker judges to be silly but not seriously harmful.

Common Mistakes

That was a foolishness move.
That was a foolish move.
'foolishness' is a noun, not an adjective. Use 'foolish' as the adjective form.
He committed many foolishness.
He committed many foolishnesses.
When countable, the plural form is 'foolishnesses'.

Word family

Synonym discussion

Sense: noun/1

All four words describe something unwise, but they differ in scope and severity. Foolishness is the broadest term — it covers any behaviour or thinking that shows poor judgment, from minor slips to serious mistakes (e.g. 'the foolishness of driving tired'). Stupidity is harsher: it suggests not just bad judgment but a lack of basic intelligence ('the sheer stupidity of the plan shocked everyone'). Folly is more formal and often carries a sense of grand, self-defeating ambition ('the folly of building a palace in the desert'). Nonsense focuses on speech or ideas that are pointless or absurd rather than on actions ('his theories are complete nonsense'). If a friend buys an overpriced gadget they cannot afford, you might call it foolishness or a folly — but calling it stupidity would sound insulting, and nonsense would miss the point.

foolishness ↗stupidity ↗folly ↗nonsense ↗

Common collocations

Adverbs

Phrases

  • act of foolishness
  • piece of foolishness
  • the foolishness of doing something

Prepositions

Etymology

Old FrenchMiddle EnglishEnglish

Foolishness is formed by adding the noun suffix '-ness' to the adjective 'foolish'. 'Foolish' comes from 'fool' (from Old French 'fol', meaning 'mad, insane, silly'), combined with the adjective suffix '-ish' ('having the quality of'). The word entered Middle English in the 13th century, first meaning 'mad, unwise' and later settling into its modern meaning of 'showing poor judgment.'