The phrase "most settling" implies that something has the ability to calm or pacify, and its antonyms would be words indicating the opposite effects. Words like "unsettling," "disturbing," "aggravating," "irritating," or "provoking" would be the opposite of "most settling." These words suggest that something causes discomfort, restlessness, and irritation instead of providing relief or comfort. An antonym for "most settling" could also be "unsettled" or "unresolved," indicating a sense of confusion or uncertainty instead of clarity and comfort. In any case, it is essential to consider the context in which an antonym is used to ensure that the intended meaning is clear.