diehard vs inveterate

diehard

adj
  • Unreasonably or stubbornly resisting change. 

  • Fanatically opposing progress or reform. 

  • Complete; having no opposite opinion of anything in a particular topic of one's values; thorough of in one's beliefs. 

noun
  • A person with such an attitude. 

inveterate

adj
  • Malignant; virulent; spiteful. 

  • firmly established from having been around for a long time; of long standing 

  • Having had a habit for a long time 

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