encouraging vs irrevocable

encouraging

adj

  • supporting by giving encouragement 

  • giving courage, confidence or hope 

  • auspicious, or bringing good luck 

noun

  • encouragement 

irrevocable

adj

  • Unable to be retracted or reversed; final. 

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