Puerileness refers to childishness, immaturity, or lack of adult-like qualities. Some antonyms of puerileness are maturity, sophistication, dignity, and wisdom, which demonstrate high-level thinking and adult-like behavior. Other antonyms of puerileness include seriousness, prudence, and intelligence, which represent a level of critical thinking and decision-making skills that are expected of an adult. Responsibility, stability, and sensibility are also opposite words of puerileness, as they are qualities that are exhibited by mature individuals. The antonyms of puerileness serve to highlight the importance of personal growth, maturation, and self-awareness required to navigate through life as a responsible and successful adult.