flat-out

1 of 2

adjective

ˈflat-ˌau̇t 

1

: being or going at maximum effort or speed

2

: out-and-out, downright

it was a flat-out lie

flat out

2 of 2

adverb

1

: in a blunt and direct manner : openly

called flat out for revolution

—Nat'l Review

2

: at top speed or peak performance

the car does 180 m.p.h. flat out

3

usually flat-out

ˈflat-ˌau̇t 

: absolutely, downright

—usually used as an intensive

is just flat-out confusing

Synonyms

Adjective

• utter
• sheer
• absolute
• unconditional
• outright
• complete
• pure
• simple
• total
• definite
• damned
• damn
• downright
• perfect
• very

Examples of flat-out in a Sentence

Adjective

regarded their son-in-law as a flat-out loser and let him know it

Adverb

I told him flat out that I have no intention of marrying him.

We asked for more time but they refused us flat out.

The car does 180 mph flat out.

Recent Examples on the Web

Adjective

Spain, for example, has flat-out refused to spend 5 percent on defense. —John Kennedy, MSNBC Newsweek, 30 July 2025

But most of it is before practice, underneath his breath, in smirks and stare-downs instead of flat-out scolds. —Alex Zietlow, Charlotte Observer, 30 July 2025

Adverb

And then obviously everyone's working flat out back in the factory. —Saajan Jogia, MSNBC Newsweek, 26 July 2025

Not surprisingly, the responses from the fintech community has been negative and, unfortunately, often overstated or flat out wrong. —Ron Shevlin, Forbes.com, 16 July 2025

Word History

First Known Use

Adjective

1906, in the meaning defined at sense 1

Adverb

1932, in the meaning defined at sense 1

Rhymes for flat-out

• about
• bailout
• blackout
• blowout
• breakout
• burnout
• buyout
• checkout
• closeout
• cutout
• devout
• dropout