A whim or caprice; behavior or a decision based on sudden moods or impulses (noun).
彼女の気まぐれで予定が変わった。
The plan changed because of her whim.
この店はオーナーの気まぐれメニューが人気だ。
This restaurant's rotating 'owner's whim' menu is popular.
犬は飼い主の気まぐれに振り回されない。
A dog shouldn't be tossed around by its owner's whims.
Capricious, fickle, or whimsical; describing someone or something prone to sudden changes in mood or behavior (na-adjective).
彼は気まぐれな人だから、約束を守らないことがある。
He's a fickle person, so sometimes he doesn't keep his promises.
天気が気まぐれで、急に雨が降り出した。
The weather is fickle, and it suddenly started to rain.
気まぐれな猫は突然膝に乗ってくる。
A capricious cat will suddenly jump onto your lap.