once and for all

  1. kesinlikle, kesin olarak, ilk ve son defa, son olarak.
    The case was settled once and for all when
    the appeal was denied: Yargıtayca reddedildikten sonra dava kesinlikle kapandı.
  2. kesinlikle, (ilk ve) son olarak, tamamıyla, bir çırpıda.
    They had to be defeated once and for all.
    I tell you once and for all that this must be done.