Definition of like sin in English:

like sin

phrase

informal
  • Vehemently or forcefully.

    ‘you can lie like sin to a keyboard’
    • ‘Picture Amneris, the slighted daughter of the Pharaohs, in Liz Taylor's inch-thick Cleopatra make-up, eyes glowing like sin, singing with a voice to move the heavens.’
    • ‘I suppose the moral of the story is that emoticons do nothing to aid the clarity of some originary emotion at the root of a comment because of the simple fact that you can lie like sin to a keyboard.’