spend money like water 挥金如土；花钱如流水；花钱大手大脚

【例句】
For years he was an absolute penny-pincher. Now that he's got a steady job, he spends money like water.
他过去好多年都是个极度吝啬的人。在有了份稳定的工作后，他开始挥金如土。

Sailors in shore leave often spend money like water.
获准离船上岸的水手往往花钱如流水。