The phrase "cut capers" refers to frolic or to behave in a mischievous and playful manner. However, the antonyms for this phrase would be to be serious or somber. To act in a formal or stiff manner would be the opposite of cutting capers. Other antonyms could include behaving calm, reserved, or somber. When someone is avoiding fun or enjoying themselves, they may be considered to be the opposite of "cutting capers." Antonyms are essential in communication as they provide a contrast that makes the meaning of the words clearer. Thus, in situations where you do not want to indulge in frivolity or mischief, you can use these antonyms to describe your demeanor.