protract vs retard

protract

verb
  • To put off to a distant time; to delay; to defer. 

  • To draw out; to extend, especially in duration. 

  • To draw to a scale; to lay down the lines and angles of, with scale and protractor; to plot. 

  • To extend; to protrude. 

  • To use a protractor. 

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