The phrase "where one's at" implies a sense of location or position. The antonyms for this phrase can vary depending on the context. For example, if the phrase is being used to refer to a person's emotional state, antonyms could include "content," "happy," or "satisfied." If the phrase is being used in a physical or geographic sense, antonyms might include "missing," "lost," or "disoriented." Alternatively, if the phrase is meant to indicate a person's level of success or achievement, antonyms might include "failing" or "unsuccessful." Ultimately, the antonyms for "where one's at" will depend on the context in which the phrase is being used.