sly as a fox vs vulpine

sly as a fox

adj
  • Very sly, very cunning. 

vulpine

adj
  • Having the characteristics of a fox; foxlike; cunning. 

  • Pertaining to a fox. 

noun
  • Any of certain canids called foxes (including the true foxes, the arctic fox and the grey fox); distinguished from the canines, which are regarded as similar to the dog and wolf. 

  • A person considered vulpine (cunning); a fox. 

How often have the words sly as a fox and vulpine occurred in a corpus of books? (source: Google Ngram Viewer )