thorough vs well-grounded

thorough

adj
  • Utter; complete; absolute. 

  • Painstaking and careful not to miss or omit any detail. 

noun
  • A furrow between two ridges, to drain off the surface water. 

well-grounded

adj
  • Of a person: having extensive knowledge of a subject. 

  • Of an argument, etc.: based on good judgment and solid reasoning. 

How often have the words thorough and well-grounded occurred in a corpus of books? (source: Google Ngram Viewer )