The phrase "mess a half" implies a state of clutter, confusion, and disorder. Its antonyms are words or phrases that denote the opposite, such as tidy, organized, neat, arranged, ordered, and uncluttered. These antonyms essentially describe a sense of cleanliness and structure that is lacking in a "mess a half" scenario. Other antonyms for the phrase could include meticulous, methodical, regimented, precise, and controlled. These words suggest a sense of discipline and attention to detail that can eliminate the chaos of a "mess a half." Ultimately, the best antonym for this phrase is simply "clean and orderly.