Out of question means something that is definitely true or certain. Antonyms for this phrase can include words like doubtful, questionable, uncertain, and debatable. These words express varying degrees of uncertainty or hesitation in making a definitive judgment. For instance, if a political candidate's victory is out of question, it means there is no doubt that the candidate will win. However, if there's uncertainty about the candidate's support or the reliability of the polls, we might say that the outcome is questionable. By using a variety of antonyms, we can convey shades of meaning that clarify the degree of certainty or confidence we have about a particular issue.