The word "undeceitful" means honest or truthful. Some other synonyms for this word include sincere, straightforward, candid, frank, legitimate, genuine, and authentic. These words can all be used to describe someone who is not deceptive or dishonest in their words or actions. Being undeceitful is a characteristic that is highly valued in both personal and professional relationships. People who are known for their honesty and integrity are often seen as trustworthy and dependable. Using synonyms for "undeceitful" can add variety and depth to your writing, while still conveying the same core meaning of honesty and truthfulness.