Old-hat refers to something that is outdated, commonly used, and no longer original. However, with the evolution of language, there are words that can be used as antonyms for the term, old-hat. Some of these words include modern, avant-garde, innovative, fresh, and newfangled. These words signify something that is new, original, and trendy, and not outdated or common. People can use these words to describe the latest fashion trends, technology, or music, and indicate their uniqueness or novelty. In summary, antonyms for the word old-hat represent something fresh, innovative, and original.