approval vs nix

approval

noun
  • Something mailed by a seller to a collector to match their stated interests; the collector can approve of or return the item. 

  • An expression granting permission; an indication of agreement with a proposal; an acknowledgement that a person, thing, or event meets requirements. 

  • An expression of favorable acceptance and encouragement; a compliment that also condones. 

nix

verb
  • To make something become nothing; to reject or cancel. 

  • To destroy or eradicate. 

intj
  • No! Not at all! 

noun
  • Nothing. 

  • A treacherous water-spirit; a nixie. 

How often have the words approval and nix occurred in a corpus of books? (source: Google Ngram Viewer )