unconcern
n. 不关心；不感兴趣；冷淡
例句
She'd mentioned it casually once, surprising him by her unconcern.
她随意地提过一次这个事，她的漠不关心让他吃惊。
《柯林斯英汉双解大词典》
She received the news with apparent unconcern.
她接到这消息时显然无动于衷。
《牛津词典》
Unconcern in his voice.
他的声音漠不关心。
