The phrase "wonder child" typically describes a young individual who possesses an exceptional talent or ability, and has achieved a high level of success in their chosen field. However, there are several antonyms for this term that suggest the opposite. For instance, terms like "mediocre," "average," or "ordinary" are often used to describe individuals who lack any particular talent, motivation, or drive. Similarly, words like "failure," "underachiever," or "disappointing" can be used to describe those who have failed to fulfill their potential or have not managed to achieve the success they once seemed destined for. Overall, while "wonder child" is a positive, aspirational term, it is important to recognize that not everyone can be a prodigy, and that there is value in average or ordinary accomplishments as well.