It is a four-character idiom and means ”for a change”. It is used to describe situations in which you refresh your mind/brain. It is often used when you are sick of the same routine work or you are feeling down.
”気晴らし”, ”息抜き”, ”リフレッシュ” are synonyms for ”気分転換”.
- Ken: 二か月後にTOEICを受けるんだけど、高得点を取る自信がない。
I’ll take the TOEIC exam in two months, but I have no confidence in getting a high score. - Leo: ん?
Why? - Ken: なんか英語が上達している気がしなくて。今回は諦めようかな。
I just feel like my English hasn’t improved very much. I wonder if I should give it up this time. - Leo: 今諦めるのはもったいない(*)よ。一生懸命勉強したんだから。んー、たまには気分転換が必要かも。
It would be a shame to stop now. You worked hard for it. Well, I think you might need a break from it sometimes. - Ken: そうかも。飲みに行かない?
Maybe. Do you want to go out for a drink? - Leo: いいよ!
Sure!
- Meg: ねぇ、やっと今度のプレゼンの準備が終わった。
Hey, I’ve finally done the preparation for the upcoming presentation. - Amy: お疲れ様!私はまだ忙しいけど、木曜には落ち着きそう。
Well done! I'm still busy, but it will settle down on Thursday. - Meg: よかったね!最近デスクで夕食をとっているから、気分転換に美味しい物でも食べに行こうよ!
Great! We’ve been eating dinner on our desks lately. Let’s go out to eat something delicious for a change! - Amy: いいね、そうしよう!
All right!