'To flat out' definitions:

Definition of 'To flat out'

From: GCIDE
  • Flat \Flat\, v. i.
  • 1. To become flat, or flattened; to sink or fall to an even surface. --Sir W. Temple. [1913 Webster]
  • 2. (Mus.) To fall form the pitch. [1913 Webster]
  • To flat out, to fail from a promising beginning; to make a bad ending; to disappoint expectations. [Colloq.] [1913 Webster]