Doorstopper, a term used for a book that is lengthy and heavy, is, without doubt, a commendable read. However, if you're looking for synonyms of this word, there are a few options you could opt for. A popular alternative to the word "doorstopper" is "tome," which is another word for an extensive and heavy volume. Another great synonym would be " brick," that suggests the book is thick, tough and heavy. Lastly, "opus" could likewise be an equivalent word for doorstopper, which typically alludes to a timeless and classic literary work that is monumental in size. Whether you prefer to use "tome," "brick," or "opus," one can't deny that these synonyms adequately convey the massiveness and grandeur of a long but rewarding read.