The word overweighing refers to something that is too significant or important, or to a person who is too heavy. Some antonyms that might be suitable for this word include "underweight," "insignificant," "unimportant," "minimal," or "negligible." These are all words that describe something that is not as important or significant as overweighing. In terms of a person's weight, the antonyms might include "lightweight," "slender," "thin," or "small," depending on the context. In any case, the antonyms for overweighing help to provide more detail and nuance to the language, allowing us to more accurately express ourselves in a variety of situations.