The phrase "most unapparent" refers to something that is not readily obvious or visible. Its antonyms include apparent, clear, obvious, visible, distinct, palpable, conspicuous, and evident. Using any of these words would indicate that something is easily perceived or understood. For example, a problem that was once "most unapparent" may now be "clear" or "evident." Similarly, if someone's feelings were previously "most unapparent," they may now be "conspicuous" or "visible." The choice of which antonym to use would depend on the context and the level of clarity desired in the communication.