vacillating vs variable

vacillating

adj
  • Liable to vacillate. 

noun
  • Vacillation. 

variable

adj
  • Likely to vary. 

  • Able to vary or be varied. 

  • Having no fixed quantitative value. 

  • Marked by diversity or difference. 

  • Tending to deviate from a normal or recognized type. 

noun
  • A quantity that may assume any one of a set of values. 

  • A shifting wind, or one that varies in force. 

  • A variable star. 

  • A symbol representing a variable. 

  • Something that is variable. 

  • Those parts of the sea where a steady wind is not expected, especially the parts between the trade-wind belts. 

  • Something whose value may be dictated or discovered. 

  • A named memory location in which a program can store intermediate results and from which it can read them. 

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