extensive vs unplumbed

extensive

adj
  • Serving to extend or lengthen; characterized by extension. 

  • Having a combined system entropy that equals the sum of the entropies of the independent systems. 

  • Having a great extent; covering a large area; vast. 

  • Considerable in amount. 

unplumbed

adj
  • Not measured for depth, with or as if with a plumb. 

  • Not assayed or measured in any way. 

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