Antonyms for the phrase "most gung-ho" would be calm, hesitant, unsure, and unenthusiastic. These words carry the opposite meaning of the phrase, which denotes a high level of enthusiasm, eagerness, and drive. For instance, if someone is hesitant about taking on a new project, they are the antithesis of a gung-ho person who would be eager to take the project head-on. Similarly, if someone is calm and unenthusiastic about a particular task, they are the opposite of the most gung-ho person who would tackle it with fervor and excitement. Therefore, these antonyms provide a clearer understanding of the meaning of the phrase and its opposite.