"Are up clouds" is not a complete English phrase or sentence, so it's difficult to provide antonyms for it. However, we can still offer some general information about antonyms. An antonym is a word that means the opposite of another word. For example, hot and cold are antonyms, as are light and dark, happy and sad, and good and bad. Antonyms are important because they provide context and nuance to our language. By using antonyms, we can convey a range of meanings and emotions, and help our communication to be more accurate and effective.