unannounced

未事先通知的、突然的、临时的

An unannounced inspection of the kitchen took place last Friday.

上周五厨房接受了一次未事先通知的检查。

未公布的、未经宣布的

The company is still testing several unannounced products.

该公司仍在测试几款尚未公布的产品。

未事先通知地、突然地

She showed up unannounced at my apartment on Sunday morning.

她星期天早上没先说一声就出现在我家。