flat out

adverb

: in a very clear and direct way

: at the fastest possible speed

—used to make a statement more forceful

Full Definition of FLAT OUT

: in a blunt and direct manner : openly <called flat out for revolution — National Review>

: at top speed or peak performance <the car does 180 m.p.h. flat out>

usually flat–out : absolutely, downright —usually used as an intensive <is just flat-out confusing>

See flat out defined for English-language learners

1932

FLAT OUT Defined for Kids

adverb

: in a very clear manner <I told him flat out to leave.>

: at top speed <We worked flat out to finish.>

Next Word in the Dictionary: flat–panelPrevious Word in the Dictionary: flat–outAll Words Near: flat out

What made you want to look up flat out? Please tell us where you read or heard it (including the quote, if possible).

Put-downs with flair

How to use a word that (literally) drives some people nuts.

Test your vocab with our fun, fast game

Ailurophobia, and 9 other unusual fears