"More half-formed" refers to something that is not fully developed or immature. Some antonyms for this term include "fully developed," "matured," "refined," "polished," "perfected," and "complete." These words suggest that the object or concept in question has reached a level of maturity, complexity, and sophistication. On the other hand, "more half-formed" evokes a sense of incompleteness, uncertainty, and imperfection. Therefore, choosing the right antonym for "more half-formed" depends on the context in which it is used and the degree of development that is desired or expected.