put out to pasture vs retard

put out to pasture

verb
  • To discontinue something. 

  • To make someone retire, especially due to advancing age. 

  • Used other than figuratively or idiomatically: see put out, to, pasture. 

retard

verb
  • To put off; to postpone. 

  • To decelerate; to slow down. 

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

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 put out to pasture and retard occurred in a corpus of books? (source: Google Ngram Viewer )