Most impugnable can be defined as questionable or open to doubt. Its antonyms include credible, trustworthy, reliable, and unquestionable. When describing something as credible, it means that it is believable, reliable, and accepted as true. Trustworthy describes something as being dependable and deserving of trust, while reliable suggests that something is dependable and can be counted on. Lastly, describing something as unquestionable means that it is beyond doubt or dispute. Considering the antonyms, we get a sense of positive connotations such as trustworthiness, dependability, and authenticity. These are all qualities that instill confidence and inspire trust in individuals and institutions.