Dictionary.com
Thesaurus.com
Synonyms

foolishness

American  
[foo-lish-nis] / ˈfu lɪʃ nɪs /

noun

  1. lack of wisdom or good judgment; foolish quality.

    Oh, the foolishness of thinking that wealth brings happiness!

  2. foolish talk, ideas, or behavior.

    How could someone with such a clever mind as yourself talk such foolishness?

  3. a foolish act, error, habit, etc..

    Shakespeare, who looks at all men as if from Mount Olympus, notes their foibles and foolishnesses, and yet smiles on them all.


Other Word Forms

Etymology

Origin of foolishness

foolish + -ness

Explanation

Foolishness is nonsense or stupidity; it's acting in a way that is silly or irrational. Throwing a temper tantrum because the lunch line is moving slowly is pure foolishness — your outburst won't make the line move any faster. When your actions show a lack of good sense or solid judgement, you're betraying your foolishness. Impulsively jumping off the garage roof into a pile of leaves is evidence of your foolishness. We can trace this word's origin back to fool and the Old French fol, "idiot," and also "blacksmith's bellows," from a root meaning "blow or swell."

Keep Reading on Vocabulary.com

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Like Mr. Platner, Mr. Duke claimed to have left all that youthful foolishness behind him.

From The Wall Street Journal Jun. 28, 2026

Mr. Clooney has never had a better role, and he burrows deeply into it with a self-interrogating combination of narcissism, foolishness, bravado and charisma.

From The Wall Street Journal Nov. 13, 2025

Diomande's act of foolishness just put the tin hat on it.

From BBC Sep. 25, 2025

The Lakers were, again, the Lakers — the version from early this season that made optimism seem nothing like foolishness.

From Los Angeles Times Dec. 16, 2024

See, my family, if you had a been part of them, you wouldn’t have time for this foolishness, your roots, so to speak.

From "The Color of Water: A Black Man's Tribute to His White Mother" by James McBride

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training