illogical vs plausible

illogical

adj
  • Contrary to logic; lacking sense or sound reasoning. 

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 illogical and plausible occurred in a corpus of books? (source: Google Ngram Viewer )