The term "most verisimilar" implies the highest level of believability or probability. Antonyms of this phrase would, therefore, refer to words that suggest the opposite. Some of the antonyms for "most verisimilar" could include "unlikely," "unlikely," "doubtful," "unbelievable," and "improbable." These words convey a sense of disbelief or skepticism, suggesting that something is not very likely to happen or be true. Other antonyms could include "incredible," "fantastical," "unrealistic," and "impossible," which suggest things that are completely unbelievable or out of the realm of possibility. By using antonyms, we can express a full range of ideas and convey different levels of believability or probability.