mendacious vs perfidious

mendacious

adj
  • Lying, untruthful or dishonest. 

  • False or untrue. 

perfidious

adj
  • Of, pertaining to, or representing perfidy; disloyal to what should command one's fidelity or allegiance. 

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