knockback vs turndown

knockback

noun
  • A rejection; a refusal. 

  • A blow that causes the recipient to fall or move backwards, a knock back; a recoil. 

  • Something that impedes or reverses progress; a setback. 

turndown

noun
  • A rejection. 

  • The operational range of a device 

  • A downturn. 

  • A downward pointing extension to a vehicle muffler. 

  • The service of turning down the bedcovers and often leaving chocolates, etc., on the pillow. 

adj
  • Made to wear with the upper part turned down. 

  • Capable of being turned down, or decreased in intensity. 

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