I.M. Montgomery is a proper noun and is not used as a word that can have synonyms. It stands for the name of a person, and therefore, cannot be replaced by any other word. It is essential to understand that certain words are specific to particular individuals or objects and cannot be interchanged. While Montgomery, or I.M.Montgomery, may have epithets such as "author," "novelist," or "columnist," none of these can serve as a synonym for their name. It is imperative to keep this in mind while using proper nouns in the English language.