flat-out

American  

[flat-out] / ˈflætˈaʊt /

adjective

Informal.

1. moving or working at top speed or with maximum effort; all-out.

   a flat-out effort by all contestants.

2. downright; thoroughgoing.

   Many of the paintings were flat-out forgeries.

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flat out Idioms  

1. In a direct manner, bluntly. For example, He told the true story flat out . [ Colloquial ; mid-1900s]

2. At top speed, as in She was running flat out to catch the train . [ Slang ; c. 1930]

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Etymology

Origin of flat-out

First recorded in 1925–30

Example Sentences

F1 bosses are due to meet in the four-week gap between Japan and the next race in Miami to discuss changes to the rules to allow drivers to push flat-out in qualifying.

From BBC • Mar. 29, 2026

I study music every night, and I have the privilege of calling someone like Babyface and just flat-out asking him, “How did you write ‘Whip Appeal’?”

From Los Angeles Times • Mar. 26, 2026

His accusation, Jones told Salon, is flat-out false.

From Salon • Mar. 11, 2026

A 2016 consumer alert from the Federal Trade Commission, which appears to be the latest on the topic, warned people against this option, saying that the deals can be risky or “even flat-out scams.”

From MarketWatch • Feb. 4, 2026

The younger one has all the kids, and you can’t just pray for a daddy to flat-out dump his babies, can you?

From "The Poisonwood Bible" by Barbara Kingsolver