The word uncustomarily implies doing something in a way that is not customary or usual. Therefore, the antonyms for uncustomarily would be words that indicate normalcy, regularity, or usual practice. Some antonyms for uncustomarily could be familiarly, commonly, typically, ordinarily, traditionally, conventionally, or habitually. These words suggest the act of doing something in a familiar or customary manner, rather than deviating from the norm. They are often used to describe actions or behavior that are expected or typical, rather than uncommon or unexpected. By using antonyms for uncustomarily, it helps to provide clarity and context to the intended meaning of a sentence.