The word "old-line" typically means something that is established or traditional. Its antonyms, on the other hand, are words that represent newness, freshness or innovation. Some antonyms for "old-line" are modern, contemporary, fresh, current, avant-garde, revolutionary, progressive, and newfangled. These words refer to something that is new or innovative, breaking away from the traditional or conventional methods. They represent the latest trends and styles, emphasizing novelty and the most recent advances. Using these antonyms can help to convey a sense of forward-thinking, modernity or cutting-edge ideas. As times change, it's important to use language that reflects these changes and keeps up with the latest trends in society.