The phrase "chip off the old block" typically means that someone is similar to their parent in character or behavior. However, antonyms for this phrase could include "unique individual," "original thinker," or "breaking the mold." These phrases suggest that the person in question is not like their parents and has their own distinctive qualities and attributes. Another possible antonym is "black sheep," which refers to someone who deviates from the norm or behaves in a way that is not typical of their family. By using these antonyms, we can describe people who are not simply replicas of their parents but have their own unique identities.