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Synonyms

know-it-all

American  
[noh-it-awl] / ˈnoʊ ɪtˌɔl /

noun

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


adjective

  1. 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  

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.

Sandwiched between his rebellious older brother, Dylan, and his know-it-all younger brother, Miles, Felix finds it easier to ignore the world around him.

From The Wall Street Journal • Jun. 12, 2026

In a 2015 biography, author Ashlee Vance described Musk as "a confrontational know-it-all" with an "abundant ego".

From BBC • Jun. 4, 2026

Volker Beck, president of the German-Israeli Society, labelled Steinmeier's comments on the war "grossly inappropriate" and said they displayed a "smug know-it-all attitude".

From Barron's • Mar. 24, 2026

I have been a know-it-all Dodger fan since the late 1950s and after last season I thought, and hoped, Clayton Kershaw would retire.

From Los Angeles Times • Sep. 20, 2025

Roland Mathers, who is kind of a know-it-all and talks like he’s forty, raises his hand and starts to speak even before she calls on him.

From "Finding Junie Kim" by Ellen Oh

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