Most sidelong refers to looking or glancing from the corners of one's eyes, or in a surreptitious or indirect manner. Antonyms for this phrase could include "direct," "straightforward," "forthright," and "blunt." These words suggest a more overt approach to communication or interaction, with a lack of hidden intent or ulterior motives. Other antonyms for most sidelong might include "honest," "transparent," or "sincere," implying a level of trustworthiness and openness in one's actions or words. Overall, antonyms for most sidelong convey a sense of integrity and authenticity, in contrast to the subtle, sneaky behavior implied by the original phrase.