sparse vs unpassable

sparse

adj
  • Having few nonzero elements 

  • Having widely spaced intervals. 

  • Not dense; meager; scanty 

unpassable

adj
  • Not able to be passed. 

  • Not able to be passed; not capable of being beaten at the net by a passing shot. 

  • Unable to pass successfully as the gender one wishes to be seen as. 

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