know-it-all

American

[noh-it-awl] / ˈnoʊ ɪtˌɔl /

noun

a person who acts as though they know everything and who dismisses the opinions, comments, or suggestions of others.

adjective

of or characteristic of a person who acts as though they know everything and who dismisses the opinions, comments, or suggestions of others.

know it all Idioms

see know all the answers.

Etymology

Origin of know-it-all

First recorded in 1930–35

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.

A voyager is curious and open to the idea that they don’t know it all.

From Slate • Jan. 14, 2024

Yet if you think you know it all, you can’t — not unless you’ve shared the court with him.

From Los Angeles Times • Feb. 19, 2023

"The 15-year-olds aren't impressed - they know it all at that age."

From BBC • Jan. 31, 2023

Lansbury was wise without being a know-it-all, even though she did actually know it all, from her gently chiding Mrs. Potts to Mrs. Jessica Fletcher.

From Salon • Oct. 12, 2022

“Now tell me about it. I want to know it all, down to the last detail.”

From "The House of the Spirits: A Novel" by Isabel Allende

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