The phrase "sunny side up" refers to cooking an egg by frying it with the yolk facing up. When it comes to antonyms for this word, we could use phrases like "over easy" or "over medium", which refer to cooking eggs with the yolk and whites flipped over and cooked until the yolk is set to the desired consistency. Alternatively, we could use the opposite of the word "sunny" to describe a mood or weather condition that is gloomy, gray, or cloudy. Overall, while there are various ways to interpret the antonyms of "sunny side up", these terms can all be used to contrast the bright and cheerful connotations of this phrase.