arcane vs explainable

arcane

adj
  • Obscure, mysterious. 

  • Understood by only a few. 

  • Extremely old (e.g. interpretation or knowledge), and possibly irrelevant. 

  • Requiring secret or mysterious knowledge to understand. 

explainable

adj
  • Able to be explained or understood 

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