impugn vs praise

impugn

verb
  • To verbally assault, especially to argue against an opinion, motive, or action; to question the truth or validity of. 

praise

verb
  • To give praise to; to commend, glorify, or worship. 

noun
  • Commendation; favourable representation in words. 

  • Worship. 

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