The phrase "have the final word" refers to being the ultimate decision-maker or having the ultimate authority in a situation. There are several synonyms for this phrase, including "have the last say," "be the ultimate arbiter," "be the definitive authority," "have the final say-so," and "be the ultimate decision-maker." These phrases all convey the idea of having the final say in a matter or being the ultimate authority on a subject. Whether in a conflict or a decision-making situation, having the final word can provide a sense of closure and completion, allowing for progress to be made and resolution to be achieved.