double-faced vs double-tongued

double-faced

adj
  • deceitful; hypocritical; treacherous 

  • Having two functional faces. 

double-tongued

adj
  • Saying one thing to one person and something different to another; double talking; deceitful in speech. 

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