impromptu

即兴的、临时的、即席的

We had an impromptu party in the office after the good news.

听到好消息后，我们在办公室临时办了一场庆祝会。

即兴地、临时地

She spoke impromptu for ten minutes and still sounded convincing.

她即兴讲了十分钟，听起来依然很有说服力。

即兴曲音乐

The pianist ended the recital with a short impromptu.

钢琴家以一首短小的即兴曲结束了独奏会。

即席演出、即兴之作

His opening remarks were a clever impromptu, not a prepared speech.

他的开场白是巧妙的即席发挥，并非事先写好的讲稿。