unallowable vs unreasonable

unallowable

adj
  • Not allowable 

  • For which an allowance may not be claimed 

unreasonable

adj
  • Without the ability to reason; unreasoning. 

  • Not reasonable; going beyond what could be expected or asked for. 

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