put back vs retard

put back

verb
  • To postpone an arranged event or appointment. 

  • To turn back; to return. 

  • To change the time in a time zone to an earlier time. 

  • To return something to its original place. 

  • To drink fast; to knock down alcohol. 

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 back and retard occurred in a corpus of books? (source: Google Ngram Viewer )