knavish vs truthful

knavish

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

truthful

adj
  • Honest, and always telling the truth. 

  • Accurately depicting what is real. 

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