The phrase "more foolheaded" implies a lack of wisdom or common sense. Antonyms for this phrase would include terms such as prudent, wise, and sensible. Additionally, cautious, circumspect, and judicious may also be considered antonyms since they suggest a level of thoughtfulness and consideration before taking action. Other potential antonyms for "more foolheaded" may include practical, logical, and reasonable, which all convey a sense of sound judgment and an ability to weigh the pros and cons of a given situation before making a decision. Overall, the antonyms for "more foolheaded" suggest a level of wisdom, intelligence and rationality that counteracts the negative connotations of the original phrase.