retard vs shun

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. 

shun

verb
  • To avoid, especially persistently; ostracize. 

  • To screen, hide. 

  • To escape (a threatening evil, an unwelcome task etc). 

  • To shove, push. 

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