whimsey

noun

1. the trait of acting unpredictably and more from whim or caprice than from reason or judgment
   1. I despair at the flightiness and whimsicality of my memory

   Synonym:    flightinessarbitrarinesswhimsicalitywhimsycapriciousness

2. an odd or fanciful or capricious idea
   1. the theatrical notion of disguise is associated with disaster in his stories
   2. he had a whimsy about flying to the moon
   3. whimsy can be humorous to someone with time to enjoy it

   Synonym:    notionwhimwhimsy