noun (n)

• the trait of resoluteness as evidenced by firmness of character or purpose(noun.attribute)

  Example:
  A man of unusual decisiveness.
  

  Synonym:
  decision
  Antonym:
  indecision, indecisiveness
  

  source: wordnet30
• the quality of being final or definitely settled(noun.attribute)

  Synonym:
  conclusiveness, finality
  Antonym:
  inconclusiveness
  

  source: wordnet30