Antonyms for the word "untruth" are words that mean the opposite of untruth or falsehood. One such antonym is "truth." Truth is the state of being in accordance with facts, reality or logic. Another antonym for untruth is "veracity," which means accuracy or truthfulness. Honesty can also be an antonym for untruth because it refers to the quality of being truthful and straightforward in character and conduct. Lastly, "veracity" is another antonym for untruth as it is the quality of being truthful and honest in word and action. All of these words bear witness to the importance of honesty, accuracy and reliability in communication.