Antonyms for the word "are tense" can be a variety of words that will depict the opposite of tense. The antonyms can be peaceful, relaxed, calm, easygoing, composed, nonchalant, placid, carefree, and unperturbed. These words will describe a person or a situation that is not worried or anxious, but instead, it is tranquil and at ease. If someone is feeling tense and wants to alleviate their stress, they can try to relax, let go of worries, take deep breaths and focus on the here and now. In doing so, they can shift their mindset from being tense to feeling peaceful, and in control of themselves.