The phrase "turn something up" is often used to indicate an increase in volume, intensity, or attention. However, it also has a range of antonyms that describe the opposite action. The most common of these is "turn something down," which means to decrease the volume, intensity, or attention. Other antonyms for "turn something up" include "mute," "lower," "soften," and "diminish." These words can be used to describe a decrease in sound, brightness, speed, or force. Knowing these antonyms can help you effectively communicate when you want something to be quieter, less noticeable, or less intense.