Idiom 170: throw cold water on

어떤 일을 하는데 격려하지 않는 경우에 사용하는 표현입니다. 찬물을 끼얹는 경우를 가리킬 때이지요.

throw cold water on = discourage

I really don't want to throw cold water on your business propsal, but I really don't think that it is a good idea.