The word "maladministered" refers to a situation where something has been improperly managed and executed. There are a number of antonyms for the word "maladministered," including "properly administered," "successfully executed," "expertly managed," and "competently handled." These antonyms signify that the task in question has been completed with skill, care, and attention to detail, without any mishaps or mistakes. For instance, a task that has been "properly administered" would have been carried out according to the rules and regulations, and with full compliance to the requirements. Therefore, by using antonyms for "maladministered," we can convey the message that something has been completed with due diligence and professionalism.