blue-gray vs hoary

blue-gray

adj
  • Of a bluish grey color. 

hoary

adj
  • Of a pale silvery grey. 

  • Old or old-fashioned; trite. 

  • Covered with short, dense, greyish white hairs. 

  • White, whitish, or greyish-white. 

  • White or grey with age. 

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