The term "in arguable" refers to a statement or premise that cannot be disputed or debated. There are several synonyms for this phrase that can be used depending on the context of the sentence. One such synonym is "undeniable," which suggests that the fact or claim is unequivocal and cannot be contradicted. Another synonym for "in arguable" is "indisputable," which emphasizes the lack of controversy surrounding the statement. "Irrefutable" is another synonym that further underscores the idea that the fact or assertion cannot be reasonably refuted. Lastly, "unquestionable" is a synonym that emphasizes the certainty and truthfulness of the statement.