"Most clownish" implies a certain level of humor, whimsy, and playfulness, but its antonyms take us to a more serious and subdued realm. Words like "dignified," "sober," and "grave" describe a personality or behavior that is solemn, composed, and restrained. People who display these traits tend to prioritize decorum over levity and act with a certain level of formality and decorousness. Alternatively, "earnest," "practical," and "pragmatic" are antonyms that suggest a no-nonsense, down-to-earth approach, one that prioritizes results and effectiveness over frivolity and shenanigans.