Whimsical

'Whim·si·cal    /ˈʰwɪmzɪkəl, ˈwɪm-/ Show Spelled[hwim-zi-kuhl, wim-]

–adjective

1.given to whimsy or fanciful notions; capricious: a pixyish, whimsical fellow.

2.of the nature

of or proceeding from whimsy, as thoughts or actions: Her writing showed whimsical notions of human behavior.

3.erratic; unpredictable: He was too whimsical with regard to his work.

Origin
1645–55; whims(y) + -ical

Related forms
whim·si·cal·ly, adverb

un·whim·si·cal, adjective

un·whim·si·cal·ly, adverb

un·whim·si·cal·ness, noun