centrifugal vs uncertain

centrifugal

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. 

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

uncertain

adj
  • Fitful or unsteady. 

  • Not certain; unsure. 

  • Not yet determined; undecided. 

  • Variable and subject to change. 

  • Unpredictable or capricious. 

  • Not known for certain; questionable. 

noun
  • Something uncertain. 

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