unnoticed
adj. 被忽视的；不引人注意的；未被注意的
例句
His departure passed unnoticed.
他神不知、鬼不觉地离开了。
《牛津词典》
I tried to slip up the stairs unnoticed.
我试图神不知鬼不觉地溜上楼梯。
《柯林斯英汉双解大词典》
His kindness did not go unnoticed by his staff.
他的厚道员工了然于心。
