无心用英文简写是：no mood.
例句：她累极了，无心跳舞。
She was very tired, and in no mood for dancing.
（图片来自网络侵删）
如果他得罪了你，那他是有嘴无心。
If he has offended you, he does not mean it.
我触犯了他完全是出于无心。
I offended him quite unintentionally.
我无心引起任何不愉快。
I don't mean there to be any unpleasantness.
我是无心说的。
I didn't say it intentionally.
他无心的勇敢行为gmh。
His Random act of bravery GMH.
