A cacophonous noise is many sounds piled on top of each other, loud and ugly, so your ears cannot rest. Think of motorbikes, a market at full shout, and a badly tuned radio, all at once. The word is not for one sharp sound; it is for the mix, and for the feeling that nothing fits. It is a grown-up, slightly bookish adjective — you will see it in writing more than hear it on the bus. People also stretch it away from sound: a cacophonous argument, cacophonous colours when too many bright things clash. That last use is a picture, not real noise, but English allows it. The opposite idea, when sounds sit well together, is a much kinder word: harmonious, or, in older fancy talk, euphonious.

嘈雜刺耳的（許多聲音擠在一起，很難聽）