- a person who acts as though he or she knows everything and who dismisses the opinions, comments, or suggestions of others.
- of or characteristic of a know-it-all.
Origin of know-it-all
First recorded in 1930–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Idioms and Phrases with know it all
know it all
see know all the answers.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.