- capricious, freakish - changeable; "a capricious summer breeze"; "freakish weather"
Antonym: predictable (indirect, via unpredictable)
- capricious, impulsive, 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"
Antonyms: nonarbitrary, unarbitrary (indirect, via arbitrary)