inadmissible vs unallowable

inadmissible

adj
  • Not admissible, especially that cannot be admitted as evidence at a trial. 

noun
  • A person who is not to be admitted (to a country, a group, etc). 

unallowable

adj
  • Not allowable 

  • For which an allowance may not be claimed 

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