在形容某人是 under a cloud 的时候意思是此人受到别人的怀疑，认为此人做了什么错事或被卷入了非法活动。

例句

After 20 years at the company, Simon left suddenly under a cloud.

Money was stolen from Jane's desk and now everyone is under a cloud of suspicion.

请注意

另一个短语 to be on cloud nine 意思是对刚刚发生的事情感到心满意足，非常高兴。

例句

The team were on cloud nine after they won the match and the tournament.