abstain vs discontinue

abstain

verb
  • Refrain from (something or doing something); keep from doing, especially an indulgence. 

  • Deliberately refrain from casting one's vote at a meeting where one is present. 

discontinue

verb
  • To consciously cease the ingestion or administration of (a pharmaceutical drug). 

  • To interrupt the continuance of; to put an end to, especially as regards commercial productions; to stop producing, making, or supplying. 

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