日落。

Use it as a noun to describe the event itself. You can say you are 'watching' the 日落. You can also use it to describe a specific time of day. It fits perfectly in a sentence like 'Let's meet at sunset.' It is very flexible and works in almost any sentence structure. You do not need complex grammar to make this work.

Use it when you are planning a romantic date. Use it when you are hiking with friends and want to reach the peak in time. It is great for photography enthusiasts talking about 'golden hour.' You can also use it in a more poetic sense in writing. It is a very safe, 'all-rounder' word for your daily life.

Do not use it if you are trying to be incredibly formal or academic. In those cases, people might use 日没, though it is rare. Also, do not confuse it with 下班, which means finishing work. Just because the sun is falling doesn't mean your boss is letting you go! Avoid using it to describe a person's decline unless you are writing a sad poem.

In Chinese culture, 日落 is often associated with the concept of 'homecoming.' Ancient poems often describe travelers feeling homesick as the sun sets. There is a famous saying: 'The setting sun is infinitely good, it is just near dusk.' This reflects a bittersweet appreciation for fleeting beauty. It is a moment for reflection and transition from work to rest.

You will often hear 落日 which is just the characters flipped. 落日 usually refers to the physical sun itself while it is setting. Another common one is 傍晚, which means 'evening' or 'dusk.' If you want to be extra romantic, you can use 夕阳. That specifically refers to the golden, glowing light of the setting sun. It sounds a bit more 'poetic' than the standard 日落.