extensional vs plausible

extensional

adj
  • Having great extent. 

  • Of or pertaining to extension. 

plausible

adj
  • Obtaining approbation; specifically pleasing; apparently right; specious. 

  • Seemingly or apparently valid, likely, or acceptable; conceivably true or likely. 

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