noun (n)

• the trait of acting unpredictably and more from whim or caprice than from reason or judgment(noun.attribute)

  Example:
  I despair at the flightiness and whimsicality of my memory.
  

  Synonym:
  arbitrariness, capriciousness, whimsey, whimsicality, whimsy
  

  source: wordnet30
• The state or quality of being flighty.(noun)

  source: webster1913