achievable vs impassable

achievable

adj
  • Capable of being achieved, which either means possible or probable. 

  • Not linked to fate or outside influences. 

impassable

adj
  • Incapable of being overcome or surmounted. 

  • Not usable as legal tender. 

  • Incapable of being passed over, crossed, or negotiated. 

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