inside out
Idioms-
With the inner surface turned out or revealed, as in He wore his shirt inside out . This expression dates from about 1600 and was soon used figuratively, as in He turned the verses inside out and revealed their hidden sense .
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Extremely well, thoroughly, especially alluding to knowing something. For example, He knows this system inside out . [First half of 1900s]
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.
Note that this week’s letter was authored by Mr. Homan, who is as serious as a heart attack about border security and who knows DHS inside out.
From The Wall Street Journal • Mar. 19, 2026
Teachers must also shoulder emotional labor in addition to knowing their subject, whether it’s history, math or English, inside out.
From MarketWatch • Mar. 9, 2026
The structure of the LHS 1903 system suggests a different pathway known as inside out planet formation.
From Science Daily • Feb. 14, 2026
That heat was enough to shatter a single pane window, creating the perfect opportunity for embers to enter and burn the house from the inside out.
From Los Angeles Times • Dec. 10, 2025
The third was to turn his room inside out looking for Miss Priest's book.
From "Jeremy Thatcher, Dragon Hatcher" by Bruce Coville
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.