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overconfidence

American  
[oh-ver-kon-fi-duhns] / ˈoʊ vərˈkɒn fɪ dəns /

noun

  1. the quality of having an unrealistically high opinion of one’s own judgment, ability, powers, etc..

    Underestimating the enemy can induce laziness and encourage overconfidence.

    Psychologists have determined that overconfidence causes people to overestimate their ability to control events and underestimate risks.

Etymology

Origin of overconfidence

over- ( def. ) + confidence ( def. )

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.

He also developed what he calls the adaptive markets hypothesis, which uses the principles of evolution to explain behaviors such as loss aversion and overconfidence.

From The Wall Street Journal • Feb. 9, 2026

Warsh’s distaste for overconfidence in models and technocratic expertise has also held throughout his career.

From Barron's • Feb. 1, 2026

The seat then contained the Labour stronghold of Harlow, but an energetic campaign, coupled with the overconfidence of the sitting Labour MP, saw Tebbit victorious in 1970.

From BBC • Jul. 8, 2025

With Ramsey standing at just over 5 feet tall, Ellie uses her size as an asset — combining nimbleness and reckless overconfidence to subdue much larger foes, people and infected alike.

From Los Angeles Times • Apr. 13, 2025

I’m not the kind of person who’s prone to premonitions or overconfidence, so I suspected that there was more to my flash than magical thinking.

From "If I Stay" by Gayle Forman

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.