impugn vs laud

impugn

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

laud

verb
  • To praise; to glorify. 

noun
  • Praise or glorification. 

  • A prayer service following matins. 

  • Hymn of praise. 

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