Antonyms for the word "most half-formed" are "fully developed," "complete," and "matured." These antonyms suggest a sense of wholeness, refinement, and accomplishment. When something is "fully developed," all its aspects have been fully realized, and it is functional and effective. A "complete" object or idea is without defects, and all parts are present and accounted for. To say something is "matured" suggests that it has reached its full potential, and it has become rich, nuanced, and complex over time. In contrast, the phrase "most half-formed" suggests an incomplete, preliminary, or unrefined state, where certain aspects still need to be worked out, finalized, or improved.