The antonyms for the word "most clunker" can be "best," "top-notch," or "high-quality." These words describe something that is in excellent working condition, efficient, and durable. They are used to denote the opposite of a clunker, which is a vehicle or any other item that is old, worn-out, and does not work properly.
For instance, a brand new luxury car can be categorized as the antonym of a clunker. Similarly, a state-of-the-art electronic gadget that functions optimally can be labeled as the antonym of a clunker. In summary, the antonyms for the word "most clunker" are descriptive of things that are exceptional, reliable, and not subject to breakdowns or malfunction.