Saying the client was a little upset after the shipping delay is an understatement.

說客戶在出貨延誤後只是有點不高興，實在太輕描淡寫了。

To call last quarter's sales growth good would be an understatement; profits nearly doubled.

說上一季的銷售成長不錯實在太保守了；利潤幾乎翻倍。

It's an understatement to say the new hire was nervous during her first board meeting.

說那位新進員工在第一次董事會上有點緊張，還真是輕描淡寫。