whimsey

noun

1. 1.A quaint and fanciful idea; a whim; playfully odd behaviour.
2. 2.An impulsive, illogical or capricious character.
3. 3.A whim (capstan or vertical drum).
4. 4.A jigsaw puzzle piece that has been cut into a recognizable shape, as if on a whim; often the shape is representative of the theme of the image used for the puzzle.