idiot
n. countablen. a very stupid person. You use this word to insult someone who has made a big mistake or is acting foolishly.
n. a person perceived as being extremely stupid or foolish. Historically used as a technical term in psychology and medicine for a person with severe intellectual disability, though this usage is now obsolete and considered highly offensive.
I felt like an idiot when I forgot my keys.
He was acting like a complete idiot at the party, shouting and knocking over drinks.
The protagonist is often portrayed as a lovable idiot whose lack of common sense is balanced by a heart of gold and an uncanny ability to stumble into success.
From Middle English idiote, ydiote, from Old French idiote (later idiot), from Latin idiota, from Ancient Greek ἰδιώτης (idiṓtēs, “a private citizen, one who has no professional knowledge, layman”), from ἴδιος (ídios, “one's own, pertaining to oneself, private”). Doublet of idiota. By surface analysis, idi- + -ot.
Commonly used as a pejorative noun; often preceded by intensifiers like 'complete', 'total', or 'absolute'.