Beseems is an old-fashioned word that is not commonly used in modern English. It means "to be suitable or appropriate" for someone or something. Some antonyms for beseems include "unsuitable," "inappropriate," "improper," "incongruous," "inapt," "unfitting," and "awkward." These words are used to describe situations, behavior, or actions that do not match the expectations, standards, or norms of a particular social or cultural context. For example, it would be inappropriate to wear a bathing suit to a formal dinner party, or it would be awkward to make jokes at a funeral. Therefore, it is important to use words that accurately convey the appropriate tone and context when describing situations or behaviors that are beseeming or not.