The term "play fool" implies acting in a silly or foolish way, but there are many antonyms that show a more serious or responsible approach. Antonyms for "play fool" include being wise, sensible, clever, astute, intelligent, or shrewd. These words suggest a more thoughtful and strategic way of behaving, opposed to being reckless or impulsive. Some other antonyms include being serious, mature, prudent, thoughtful, or responsible. These antonyms can be used to describe someone who is careful, competent, and capable of making good decisions. By contrast, "play fool" suggests a lack of thoughtfulness and can often be associated with foolishness or naivety.