The phrase "more thoroughgoing" can be defined as a complete or comprehensive approach to something. Its antonyms could be "superficial," meaning that something is done or performed in a superficial or shallow manner, lacking depth or detail. Another antonym could be "partial," which means that someone has only dealt with a part or a portion of something rather than approaching it comprehensively. Additionally, "incomplete," which refers to something that has not been finished or done correctly, can be seen as another antonym for "more thoroughgoing." Therefore, it is important to understand the opposite meaning of "more thoroughgoing" to convey the intended ideas effectively.