discourage vs sign off on

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 

sign off on

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