n/a vs unpermissible

n/a

adj

  • not applicable 

  • not approved 

  • non-assessable 

  • not attested 

  • not available 

  • not assigned, no assignment 

unpermissible

adj

  • Not permissible. 

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