interrupt vs retard

interrupt

verb
  • To disturb or halt (an ongoing process or action, or the person performing it) by interfering suddenly. 

  • To assert to (a computer) that an exceptional condition must be handled. 

  • To divide; to separate; to break the monotony of. 

noun
  • An event that causes a computer or other device to temporarily cease what it was doing and attend to a condition. 

retard

verb
  • To keep delaying; to continue to hinder; to prevent from progressing. 

  • To put off; to postpone. 

  • To decelerate; to slow down. 

noun
  • Retardation; delay. 

  • A slowing down of the tempo; a ritardando. 

  • A person or being who is extremely stupid or slow to learn. 

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