ever-changing vs mutable

ever-changing

mutable

noun
  • Something mutable; a variable or value that can change. 

adj
  • Having a value that is changeable during program execution. 

  • Changeable, dynamic, evolutive; inclined to change, evolve, mutate. 

  • Being one of the signs Gemini, Virgo, Sagittarius and Pisces, associated with adaptability, flexibility and sympathy. 

How often have the words ever-changing and mutable occurred in a corpus of books? (source: Google Ngram Viewer )