The antonyms for the phrase "most close by" could be interpreted in a few different ways. One possibility is to focus on the concept of distance, so antonyms might include "far away," "distant," or "remote." Another possibility is to consider the level of familiarity or proximity, so antonyms could include "unfamiliar," "distant," "estranged," or "unknown." Depending on the context in which the phrase is being used, there could be a variety of antonyms that make sense. Ultimately, it's important to consider the specific nuance of the phrase and choose antonyms that accurately convey the intended meaning.