retard vs shelve

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. 

shelve

verb
  • To set aside; to quit or postpone. 

  • To place on a shelf. 

  • To furnish with shelves. 

  • To slope; to incline; to form into shelves. 

  • To have sex with. 

  • To take (drugs) by anal or vaginal insertion. 

noun
  • A rocky ledge or shelf. 

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