noun (n)

• the capability of conscious choice and decision and intention(noun.cognition)

  Example:
  The exercise of their volition we construe as revolt.
  

  Synonym:
  will
  

  source: wordnet30
• the act of making a choice(noun.act)

  Example:
  Followed my father of my own volition.
  

  Synonym:
  willing
  

  source: wordnet30
• The act of willing or choosing; the act of forming a purpose; the exercise of the will.(noun)

  source: webster1913