idiocy

American  

[id-ee-uh-see] / ˈɪd i ə si /

noun

plural

idiocies

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.

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idiocy British  

/ ˈɪdɪəsɪ /

noun

1. (not in technical usage) severe mental retardation

2. foolishness or senselessness; stupidity

3. a foolish act or remark

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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”; 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.

Example Sentences

Sometimes you have to break away from heavy, sodden reality and go straight into joyful idiocy.

From The Wall Street Journal • Oct. 9, 2025

Aside from the idiocy of the move itself, one of the most egregious screw-ups on that chat was the efense secretary sharing imminent war plans.

From Salon • Apr. 21, 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

And now, because of my idiocy, she has tracked me right to my family.

From "Legend" by Marie Lu

Related Words

• insanity
• lunacy
• madness