The antonyms for the word "un-manliest" would be words like "manliest," "heroic," "brave," "courageous," and "gallant." These words describe traits that are traditionally associated with masculinity and strength. Adjectives like "wimpy," "timid," "weak," "feminine," and "effeminate" would be considered antonyms for "manliest." These adjectives describe traits that are traditionally associated with weakness or a lack of masculinity. Overall, it's important to remember that there is no one way to be "manly" and that we should embrace and celebrate a diversity of traits and behaviors regardless of gender.