Antonyms for the word "tensed up" would include relaxed, calm, composed, untroubled, at ease, peaceful, and carefree. When we feel tense, our muscles tighten and our minds become stressed. To alleviate this feeling, it's essential to calm down and relax. Take deep breaths, listen to soothing music, or take a walk in nature. Living a healthy lifestyle that includes exercise and proper diet can also help reduce tension. Practicing meditation and mindfulness can also aid in feeling more centered, relaxed, and at ease. It's essential to find what works for you and incorporate these practices into your daily life to decrease tension and promote overall well-being.