The term "keys up" denotes a state of being stimulated or excited, but there are several antonyms associated with it. One of the most prominent antonyms is "calms down," which denotes a state of peace or tranquility. Another opposite of "keys up" is "relaxes," which means to loosen up or unwind. Other antonyms include "depresses," "saddens," and "discourages," all of which connote a state of negative emotions. Overall, the antonyms of "keys up" explain the opposite emotional states that individuals can exhibit in different situations, and they are helpful in conveying the subtle nuances of language.