centrifugal vs idler

centrifugal

noun
  • A rotating machine used to separate massecuite into sugar crystals and molasses. 

adj
  • Tending, or causing, to recede from the center. 

  • Expanding first at the summit, and later at the base, as a flower cluster. 

  • Having the radicle turned toward the sides of the fruit, as some embryos. 

idler

noun
  • A mechanical device such as a pulley or wheel that does not transmit power, but supports a moving belt etc. 

  • One who idles; one who spends his or her time in inaction. 

  • One who idles; a lazy person; a sluggard. 

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