Antonyms for the phrase "hold an opinion" include several words and phrases that convey a lack of certainty or conviction. For instance, "doubt," "uncertain," "unsure," "wavering," "indecisive," "ambiguous," and "undecided" all suggest that one does not hold a firm opinion or belief. Similarly, "ignore," "disregard," "dismiss," "neglect," "shrug off," and "brush aside" imply a lack of interest or concern about forming an opinion on a particular topic. Lastly, "open-minded," "neutral," "impartial," and "objective" suggest that one is willing to consider all perspectives and information before forming an opinion, rather than holding a fixed viewpoint.