When it comes to finding antonyms for the word "most backnumber," many options come to mind. One antonym of the word is "contemporary," which refers to something that is current, modern, or up-to-date. Another antonym is "cutting-edge," which describes something that is innovative, avant-garde, or at the forefront of its field. "Latest" and "new" are also antonyms that are commonly used to contrast with the idea of something being outdated, ancient, or obsolete. Additionally, terms like "fresh," "modern," and "recent" can all be seen as antonyms to "most backnumber," pointing towards the newness or modernity of an object or idea.