means Playfully fanciful and unpredictable, governed by sudden fancy rather than reason or plan.

from From 'whimsy,' a sudden notion or fanciful idea, which grew out of the older 'whim-wham' — a quaint trinket or odd fancy from the 16th century. 'Whim-wham' itself is one of those bouncy reduplicated words, possibly echoing earlier Scandinavian terms for whirling or trembling, though its exact roots are foggy. By the late 1600s 'whim' had settled into meaning a passing caprice, and 'whimsical' followed close behind to describe anyone ruled by such delightful gusts of fancy.