impassable vs inaccessible

impassable

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

  • Incapable of being overcome or surmounted. 

  • Not usable as legal tender. 

inaccessible

adj
  • Not able to be reached; unattainable. 

  • Not able to be accessed; out of reach; inconvenient. 

noun
  • An uncountable regular cardinal number that is a limit cardinal. 

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