know-it-all

[noh-it-awl]

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.

Word History and Origins

Origin of know it all¹

First recorded in 1930–35

Idioms and Phrases

see know all the answers.

Example Sentences

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.

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He could come off as a know-it-all, and he tended to ramble when speaking.

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Of course, being a kid is full of trial and error, especially when you’re a know-it-all.

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More than this, it redeems Daniel too, highlighting his transformation from a self-righteous know-it-all into a man who makes peace with some mysteries and finds balance with the man he once tolerated.

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He talks about movies not with a know-it-all territorialism but rather an inclusive camaraderie.

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Related Words

• smart aleck 
• wise guy