1. 云 (yún): This is the most common and general way to write "cloud" in Chinese. It can refer to a cloud in the sky, a cloud of smoke, or even a metaphorical cloud of something like worry or doubt.
2. 云彩 (yúncǎi): This means "cloud" in the sense of a visible formation in the sky. It is used more specifically to describe the appearance of clouds.
3. 乌云 (wūyún): This means "dark cloud" or "storm cloud." It implies a sense of gloom or danger.
4. 云朵 (yúnduǒ): This is a more poetic way to say "cloud." It literally means "cloud tuft" and emphasizes the fluffy, cottony texture of clouds.
5. 云层 (yúncéng): This means "cloud layer" and refers to the layers of clouds in the atmosphere.
6. 云雾 (yúnwù): This means "cloud mist" and refers to a dense fog or mist that resembles clouds.
The specific translation you choose will depend on the specific meaning you want to convey. For example, if you are talking about the clouds in the sky, you would use 云 or 云彩. If you are talking about a metaphorical cloud of worry, you would use 云.