allowable vs morphological

allowable

adj
  • Appropriate; satisfactory; acceptable. 

  • Intellectually admissible; valid; probable. 

  • Able to be added or deducted in consideration of something. 

  • Permissible; tolerable; legitimate. 

noun
  • permitted amount or activity. 

morphological

adj
  • Of, or pertaining to, morphology. 

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