retard vs startle

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. 

startle

verb
  • To move suddenly, or be excited, on feeling alarm; to start. 

  • To excite by sudden alarm, surprise, or apprehension; to frighten suddenly and not seriously; to alarm; to surprise. 

noun
  • A sudden motion or shock caused by an unexpected alarm, surprise, or apprehension of danger. 

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