and that's flat - definition and synonyms

or and that's final

  1.   From our crowdsourced Open Dictionary
    used at the end of a sentence to emphasize that you have made a decision and you will not change it

    She's not coming with us, and that's flat!

    I'm not going with you, and that's final!

    Submitted by Caleb Judy from United States on 13/02/2016