inadequacy vs inexplicability

inadequacy

noun
  • The state of being inadequate. 

  • A lack of competence or ability. 

  • A shortage of required material. 

inexplicability

noun
  • The state of being difficult to account for; the state of being inexplicable. 

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