knavish vs principled

knavish

adj
  • Having the characteristics of a knave; mischievous, roguish, waggish, rascally or impertinent 

principled

adj
  • Based on, having, or manifesting principles 

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

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