discourage vs keep under

discourage

verb
  • To extinguish the courage of; to dishearten; to depress the spirits of; to deprive of confidence; to deject. 

  • To persuade somebody not to do (something). 

noun
  • Lack of courage 

keep under

verb
  • To hold in subjection; hence, to oppress. 

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