retard vs streak

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. 

streak

verb
  • To create streaks. 

  • To have or obtain streaks. 

  • To run naked in public. (Contrast flash) 

  • To move very swiftly. 

  • To run quickly. 

noun
  • The color of the powder of a mineral. So called, because a simple field test for a mineral is to streak it against unglazed white porcelain. 

  • The act of streaking, or running naked through a public area. 

  • An irregular line left from smearing or motion. 

  • A strake. 

  • A continuous series of like events. 

  • A moth of the family Geometridae, Chesias legatella. 

  • A tendency or characteristic, but not a dominant or pervasive one. 

  • A rung or round of a ladder. 

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