flat out - definition and synonyms

phrase informal
  1. 1
    as quickly or with as much effort as possible

    He worked flat out from morning until night.

  2. 2
    directly, without trying to avoid offending or upsetting people

    Michael said flat out that he didn’t believe me.

  3. 3
    mainly American completely and without doubt

    He was just flat out wrong.

See also main entry: flat