The antonyms of "GREEN SPEED" are words that convey the opposite meaning of this phrase. For "green," antonyms can be brown, withered, or dead. These words describe something that is not fresh, alive, or filled with life. For "speed," antonyms can be slow, leisurely, or relaxed. These words describe something that is not fast, quick, or filled with energy. When we combine these antonyms, we can have phrases like "brown slow," "withered leisurely," or "dead relaxed." These phrases paint a picture of something that is not vibrant, lively, or moving at a fast pace.