One's mood or feeling — a temporary mental or emotional state (e.g., feeling good, tired, upset).
今日は気分がいいから散歩に行こう。
I'm in a good mood today, so let's go for a walk.
天気が悪いとどうしても気分が落ち込む。
When the weather is bad, I inevitably feel down.
気分転換にカフェで本を読む。
I read a book at a café to change my mood.
気分次第で予定を変えるのはよくない。
It's not good to change plans depending on your mood.