Back number is a term used to refer to old, outdated, or obsolete information or items. The antonyms of back number are contemporary, modern, or current. These words are opposite in meaning as they signify something that is new, up-to-date and relevant in the present time. Examples of opposites for back number include cutting-edge, novel, fresh, modern, trendy, and state-of-the-art. In today's fast-paced society, it is essential to stay current with the latest trends and technology to remain relevant and competitive. Therefore, it is crucial to update old information with contemporary data and stay ahead of the back number.