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.

—National 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 of flat-out

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

Poor Sofia Coppola, a last-minute replacement for Winona Ryder, flat-out couldn’t act. —Glenn Whipp, Los Angeles Times, 17 Feb. 2026

The singer refused to flat-out say the Eagles are calling it quits. —Thor Christensen, Dallas Morning News, 11 Feb. 2026

Adverb

Miami’s new decision-makers flat out admit there’s no certainty Tagovailoa will be part of the organization moving forward, and the only thing that will likely change that could be a series of swings and misses in free agency and the NFL Draft. —Omar Kelly, Miami Herald, 13 Feb. 2026

If a 17-game schedule is too much from a player safety standpoint, 18 is flat out overkill. —Jim Alexander, Oc Register, 6 Feb. 2026

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