retard vs unblock

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. 

unblock

verb
  • To remove or clear a block or obstruction from. 

  • In whist, to throw away a high card so as not to interrupt one's partner's long suit. 

  • To free or make available. 

  • To enable communication again, via telephone, instant messaging, etc., with (somebody previously blocked). 

noun
  • The removal of a block or blockage. 

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