Acid rigor is a chemical process that occurs in tissues resulting in a decrease in pH and the gradual stiffening of muscles. Antonyms for acid rigor include terms such as flexibility, pliability, suppleness, elasticity, and fluidity. These antonyms describe the opposite condition of acid rigor, where muscles or tissues are soft, pliant, and capable of movement. In the context of biology or physiology, antonyms for acid rigor could also include relaxation, smoothness, or looseness, which represent physiological states where muscles are not rigid but instead free from tension or contraction. Overall, antonyms for acid rigor describe a state of malleability, elasticity, and responsiveness in tissues, which contribute to their overall health and functionality.