In the TV show 'M*A*S*H', what was the nickname of Corporal Walter O'Reilly?

The nickname of Corporal Walter "Radar" O'Reilly in the TV show "MASH" is Radar because of his exceptional ability to anticipate and respond to orders before they were given. He had a keen sense of intuition and a remarkable ability to predict the needs of his fellow soldiers and superiors. This skill, coupled with his extraordinary hearing abilities, earned him the nickname "Radar," as he seemingly had a radar-like ability to foresee events and anticipate orders before they were actually given.