noun (n)

• the quality of being capable of mutation(noun.attribute)

  Synonym:
  mutableness
  Antonym:
  fixity, immutability, immutableness
  

  source: wordnet30
• The quality of being mutable, or subject to change or alteration, either in form, state, or essential character; susceptibility of change; changeableness; inconstancy; variation.(noun)

  source: webster1913