WordReference Random House Learner's Dictionary of American English © 2026
ˈflat-ˈout,
adj. [Informal.]
WordReference Random House Unabridged Dictionary of American English © 2026- Informal Termsusing full speed or all of one's resources:a flat-out effort.
- Informal Termscomplete:a flat-out forgery.
flat-out
(flat′out′),USA pronunciation adj. [Informal.]
- Informal Termsmoving or working at top speed or with maximum effort;
all-out:a flat-out effort by all contestants. - Informal Termsdownright;
thoroughgoing:Many of the paintings were flat-out forgeries.
- 1925–30
'flat-out' also found in these entries (note: many are not synonyms or translations):