The phrase "most thorough going" refers to something that is complete and intensive. Some of the antonyms for this phrase include "superficial," "incomplete," and "shallow." When something is described as superficial, it means that it lacks depth or substance. An incomplete task, on the other hand, is one that is not finished, making it the opposite of the thorough going. Shallow refers to something that lacks depth, significance, or importance. These antonyms help to provide a better understanding of what the phrase means, and offer alternative descriptions that can be used to communicate different meanings.