Unconstrict is a word that describes the act of loosening or relaxing. The antonyms of unconstrict would be words that describe the opposite action of tightening or restricting. Some antonyms for unconstrict would include constrict, tighten, compress, bind, pinch, grip, and hold tight. These words express tension or constriction of some sort. They suggest a more limited, rigid or constricted state of being. On the other hand, when we use words like loosen, relax, ease, release, or slacken, we describe a sense of open and relaxed state where things are free to move and flow. These words express a feeling of freedom and ease.