flat-out

[ flat-out ]
/ ˈflætˈaʊt /

adjective Informal.

moving or working at top speed or with maximum effort; all-out: a flat-out effort by all contestants.
downright; thoroughgoing: Many of the paintings were flat-out forgeries.

Origin of flat-out

First recorded in 1925–30
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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