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Meaning of flat-out

flat-out

Pronunciation: (flat'out'), [key]
— adj. Informal.
  1. moving or working at top speed or with maximum effort; all-out: a flat-out effort by all contestants.
  2. downright; thoroughgoing: Many of the paintings were flat-out forgeries.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.