crazy like a fox vs double-faced

crazy like a fox

adj
  • Behaving in a foolish, frivolous, or uncomprehending manner as a ruse for concealing clever deeds or deeper intentions. 

double-faced

adj
  • deceitful; hypocritical; treacherous 

  • Having two functional faces. 

How often have the words crazy like a fox and double-faced occurred in a corpus of books? (source: Google Ngram Viewer )