Definition

Noun: A person who behaves as if they know everything and is often annoyingly unwilling to listen to advice or accept information from others.

Usage

This word is used to describe a person whose attitude is characterized by arrogance and an unwarranted display of knowledge. It is typically a critical or pejorative term.

Examples

• She's such a know-it-all that it's impossible to have a discussion with her; she dismisses every point you make.
• Don't be a know-it-all in the meeting. Listen to what the experienced engineers have to say.
• His know-it-all attitude made him very unpopular with his classmates.

Advanced Usage

• The term can function attributively as a compound modifier before a noun (e.g., , ).
• It is often used in direct address or description to express frustration or criticism.

Variants and Related Words

• Smart aleck / Smarty-pants (noun): Informal, slightly more childish synonyms for a know-it-all, often implying cheekiness.
• Pseudointellectual (noun): A person who pretends to be knowledgeable or cultured.
• Pedant (noun): A person who is excessively concerned with minor details and rules, often showing off their book learning.

Synonyms

• Wise guy
• Smart aleck
• Smarty
• Braggart (though this emphasizes boasting more than false knowledge)

Antonyms

• Novice
• Beginner
• Humble person
• Open-minded individual

Idioms and Related Phrases

• To have all the answers: To act as if one knows everything. (e.g., )
• A little knowledge is a dangerous thing: Proverb suggesting that people who know a little often mistakenly believe they know a lot, which can lead to poor decisions. This concept is closely related to the behavior of a know-it-all.

Noun

1. someone who thinks he knows everything and refuses to accept advice or information from others