The antonyms for the word "more unproven" can be "proven", "verified", "confirmed", "established" or "tested". These are the opposite descriptions or terms which denote the idea that something has been tried, tested and found to be true or accurate. These antonyms serve as contrasting phrases to "more unproven" and hence suggest that a certain proposition, theory or claim has been substantiated or proven to be valid. Therefore, the use of antonyms helps to strengthen or weaken the credibility of a statement or argument, depending on the context in which they are employed.