Noun

• 1. an odd or fanciful or capricious idea;

  "the theatrical notion of disguise is associated with disaster in his stories"

  "he had a whimsy about flying to the moon"

  "whimsy can be humorous to someone with time to enjoy it"

• 2. the trait of acting unpredictably and more from whim or caprice than from reason or judgment;

  "I despair at the flightiness and whimsicality of my memory"