subtle vs vulpinary

subtle

adj
  • Cunning, skillful. 

  • Tenuous; rarefied; of low density or thin consistency. 

  • Barely noticeable, not obvious, indistinct. 

  • Cleverly contrived. 

  • Insidious. 

  • Hard to grasp; not obvious or easily understood. 

vulpinary

adj
  • Crafty, sly, shrewd. 

  • Not spiritual or religious; common. 

  • Relating to a fox. 

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