exorable vs unimpregnable

exorable

adj
  • Capable of being moved or persuaded. 

unimpregnable

adj
  • Not impregnable; capable of being pierced or assailed. 

  • Incapable of being impregnated; impermeable or infertile. 

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