whimsical -
determined by chance or impulse or whim rather than by necessity or reason; "a capricious refusal"; "authoritarian rulers are frequently capricious"; "the victim of whimsical persecutions"
arbitrary based on or subject to individual discretion or preference or sometimes impulse or caprice; "an arbitrary decision"; "the arbitrary rule of a dictator"; "an arbitrary penalty"; "of arbitrary size and shape"; "an arbitrary choice"; "arbitrary division of the group into halves"
