low是“低的”，water是“水”，in low water直译就是：“水位低”，引申为拮据、缺钱。

【例句】
He's in low water because he's been unemployed for a couple of months.
他很拮据因为他失业已经几个月了。

He did not wish the public to know that he was in low water.
他不愿意大家知道他经济拮据。