Dictionary.com
Thesaurus.com
Synonyms

idiocy

American  
[id-ee-uh-see] / ˈɪd i ə si /

noun

  • idiocies
    plural
  1. utterly senseless or foolish behavior; a stupid or foolish act, statement, etc..

    All this talk of zombies coming to attack us is pure idiocy.

    Synonyms:
    folly, inanity, foolishness
  2. Psychology. (no longer in technical use; considered offensive) an intellectual disability, previously classified in a now obsolete rubric of developmental disorders as having a mental age of less than three years old and an intelligence quotient under 25.


idiocy British  
/ ˈɪdɪəsɪ /

noun

  1. (not in technical usage) severe mental retardation

  2. foolishness or senselessness; stupidity

  3. a foolish act or remark

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Noun Inflected Forms

Etymology

Origin of idiocy

First recorded in 1520–30; from Medieval Latin idiotia “imbecility,” from Hellenistic Greek idiōteía “uncouthness, ignorance,” Greek “state of being a private person”; see origin at idiot, -cy

Explanation

Idiocy is extreme stupidity. If you skied down a dangerous slope with little experience and no helmet, your friends would be right to comment on your idiocy. When someone behaves in a foolish way, showing no evidence that they've thought about their actions, you can call it idiocy. You could scold your little brother, "Your idiocy in the bouncy house made it impossible for anyone else to have fun at the party," or criticize the idiocy of your governor's decision to refuse federal funds for school lunches. The noun idiot came before idiocy, and both words originally had psychiatric meanings that are now obsolete.

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:

A few days later I saw a friend who knows his foreign affairs and he said, “Do you believe the idiocy of this guy?”

From The Wall Street Journal Oct. 9, 2025

Utter asininity is the bread and butter of “The Naked Gun,” and the movie milks cop idiocy for all its worth.

From Salon Aug. 1, 2025

I think it’s tragedy disguised as comedy, tragedy masquerading as comedy, in that the satire is in response to tragic idiocy and absurdity that is better responded to with humor than pure anger.

From Los Angeles Times Jan. 23, 2024

I call on George Santos to engineer a crypto fleece or a phishing operation or really any scheme worthy of his singular, astonishing idiocy.

From Slate Nov. 16, 2023

I suppose every mother is reduced to idiocy when describing her firstborn, but, oh, he is a beauty—large and dark like his father, but with the bright blue eyes of the Bradshaws.

From "Jacob Have I Loved" by Katherine Paterson

A cranky novelist ensconced in a swanky setting, railing at the idiocies of the contemporary world.

From Washington Post Jul. 10, 2021

What follows is a non-exhaustive list of some of the major idiocies of the year.

From The New Yorker Dec. 13, 2019

The essay that attracted my attention connects data points including the media tour of Bryan Goldberg, upon whom entertaining opprobrium has been heaped for his idiocies in launching Bustle.

From Slate Oct. 2, 2013

One prepared to take the piss out of the idiocies of his own party as well the government.

From The Guardian Feb. 13, 2013

A small victory or two would help her to tolerate their idiocies and would stop her from going crazy.

From "Matilda" by Roald Dahl

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

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

Start training