herd vs retard

herd

verb
  • To move or drive a herd. 

  • To manage, care for or guard a herd 

  • To act as a herdsman or a shepherd. 

  • To unite or associate in a herd 

  • To associate; to ally oneself with, or place oneself among, a group or company. 

  • To unite or associate in a herd; to feed or run together, or in company. 

  • To form or put into a herd. 

noun
  • A number of domestic animals assembled together under the watch or ownership of a keeper. 

  • Any collection of animals gathered or travelling in a company. 

  • A crowd, a mass of people or things; a rabble. 

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