moving or working at top speed or with maximum effort; all-out.
a flat-out effort by all contestants.
downright; thoroughgoing.
Many of the paintings were flat-out forgeries.
In a direct manner, bluntly. For example, He told the true story flat out . [ Colloquial ; mid-1900s]
At top speed, as in She was running flat out to catch the train . [ Slang ; c. 1930]
First recorded in 1925–30
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"I'm not trying to be negative but the Mercedes is flat-out quicker," Hamilton said.
From BBC • Jul. 4, 2026
Given all that, it is flat-out wrong to say that AI adoption is stagnating, says Ethan Mollick, a Wharton professor who studies how companies adopt AI.
From The Wall Street Journal • Jun. 7, 2026
Romero explains how the Supreme Court is essentially treating Callais “as a stand-in for principles that the justices either did not discuss in that case or flat-out claimed to reject.”
From Slate • May 21, 2026
Animal activists noted that CNMI's new guidelines fell short of the flat-out bans on fur seen in other fashion weeks, but nevertheless called it progress.
From Barron's • May 15, 2026
He felt like he’d run flat-out from Mirror Tech to the McKays’ and like his mind had been stretched to its limit.
From "Boy 2.0" by Tracey Baptiste
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.
