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

Rose Byrne’s gonzo portrayal of a woman over the edge is flat-out brilliant, the most powerful thing she’s done and one of the best performances of the year. —Bill Goodykoontz, AZCentral.com, 24 Oct. 2025

Their offense lit up the scoreboard and their defense flat-out dominated. —Mike Jones, New York Times, 2 Oct. 2025

Adverb

The White House flat out denied that report, though TMZ stands by it. —Madeleine Marr, Miami Herald, 22 Oct. 2025

That's because Silent Hill f is one of the boldest, darkest, goriest, grimmest, and flat out best games in the entire series; a tremendous achievement that just over a year ago seemed unfathomable. —Vincent Acovino, NPR, 22 Sep. 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