The phrase "most unblenching" refers to someone who is extremely resolute and steadfast in their beliefs, actions, or attitude. Antonyms for this phrase would be words that suggest a lack of courage, determination, or conviction. Some possible antonyms include hesitant, uncertain, fearful, timid, weak-willed, vacillating, or indecisive. These words describe individuals who lack the resolve or confidence to stand up for their beliefs or take decisive action. In contrast to the unwavering demeanor of someone who is most unblenching, these antonyms suggest a lack of confidence, conviction, or courage in the face of adversity or challenge.