hinder vs retard

hinder

verb
  • To delay or impede; to keep back, to prevent. 

  • To make difficult to accomplish; to act as an obstacle; to frustrate. 

adj
  • Of or belonging to that part or end which is in the rear or hind, or which follows. 

noun
  • The buttocks. 

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