perfidious vs principled

perfidious

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

principled

adj
  • Based on, having, or manifesting principles 

  • strongly adhering to, or heedful of, guiding beliefs or moral rules 

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