Definition of one-eighty in English:

one-eighty

noun

  • 1mainly US informal A turn to face in the opposite direction.

    • ‘I sat in front of them, turning my desk in a one-eighty’
    1. 1.1A complete reversal in attitude or opinion.
      • ‘her personality did a one-eighty and she was back to being sweet and caring’

Origin

1920s a spelling of 180 degrees.