The word "more imposturous" itself is a rare occurrence in the English language. However, if we break down the word into its two parts, "imposturous" and "more," we can find antonyms for each part. Antonyms for "imposturous" include honest, truthful, genuine, and sincere. These words represent the opposite of being deceitful, dishonest, or fraudulent. On the other hand, antonyms for "more" include less, fewer, diminished, and reduced. These words denote the opposite of increasing or adding more of something. In conclusion, the antonyms for "more imposturous" involves being honest and decreasing the level of deceit or dishonesty.