noun (n)

• an absence of emotion or enthusiasm(noun.feeling)

  source: wordnet30
• the trait of lacking enthusiasm for or interest in things generally(noun.attribute)

  Synonym:
  indifference, numbness, spiritlessness
  

  source: wordnet30
• Want of feeling; privation of passion, emotion, or excitement; dispassion; -- applied either to the body or the mind. As applied to the mind, it is a calmness, indolence, or state of indifference, incapable of being ruffled or roused to active interest or exertion by pleasure, pain, or passion.(noun)

  source: webster1913