Definition
This idiom describes a person who speaks very little, but in fact possesses a wealth of knowledge or a depth of character; often used to describe someone who does not easily reveal their emotions or thoughts, but has a profound inner life.
靜水流深，深藏不露。
Don't be fooled by his quiet demeanor; he's a very deep and thoughtful person, a real 'still waters run deep' kind of guy.
不要被他安靜的舉止所欺騙；他是一個非常深沉且深思熟慮的人，是真正的『靜水流深』類型的人。
She always observes everything quietly, rarely speaking, but her insights are always so profound; truly, 'still waters run deep'.
她總是安靜地觀察一切，很少說話，但她的見解總是非常深刻；真是『靜水流深』。
He might seem ordinary at first glance, but after talking to him, you realize how profound he is; indeed, 'still waters run deep'.
乍看之下他可能很普通，但和他交談後，你會發現他有多麼深刻；確實，『靜水流深』。