"Chip off old blocks" is a colloquial phrase used to describe a person who resembles their parents in terms of appearance or behavior. The antonyms for this phrase would be "black sheep" or "odd one out". These antonyms describe individuals who are significantly different from their family and do not possess the same qualities or characteristics. They stand out from the rest of the family for various reasons, such as having opposing views, an unusual personality, or appearance. While "chip off old blocks" is a positive term to describe family resemblance, the antonyms accentuate the concept of individuality and being unique despite one's familial ties.