The phrase "be of the opinion" denotes a particular belief or view held by someone. Antonyms for this phrase would, therefore, involve expressions that reflect an absence or lack of opinion. Some examples of antonyms to "be of the opinion" include phrases such as "have no particular view," "be ambivalent," "be undecided," or "remain neutral." Other antonyms can also denote a contrasting or contradictory viewpoint, such as "disagree," "hold a different belief," or "contradict." Synonyms such as "think," "believe," or "consider," could also be used interchangeably with "be of the opinion." Understanding antonyms to common phrases can be helpful in developing a well-rounded understanding of language use.