acceptable vs unallowable

acceptable

adj
  • worthy, decent, sure of being accepted or received with at least moderate pleasure 

  • Barely worthy, less than excellent; passable. 

unallowable

adj
  • Not allowable 

  • For which an allowance may not be claimed 

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