impeach vs retard

impeach

verb
  • To hinder, impede, or prevent. 

  • To bring a legal proceeding against a public official. 

  • To charge with impropriety; to discredit; to call into question. 

  • To demonstrate in court that a testimony under oath contradicts another testimony from the same person, usually one taken during deposition. 

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