hoary vs septuagenarian

hoary

adj
  • Old or old-fashioned; trite. 

  • Covered with short, dense, greyish white hairs. 

  • Of a pale silvery grey. 

  • White, whitish, or greyish-white. 

  • White or grey with age. 

septuagenarian

adj
  • Of or related to seventysomethings. 

noun
  • Synonym of seventysomething: a person between 70 and 79 years old. 

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