a young person who acts in an uncontrolled way, for example not obeying their parents, drinking too much alcohol, etc.

She was a wild child when younger, but is now clean and sober. 她年轻的时候是个野孩子，但现在已经戒掉，不再酗酒了。

a child who has grown up separated from normal human society

He researched tales of wild children - either those who had grown up alone or with animals. 他研究了野孩子的故事——在野外独自长大或和动物一起长大的孩子。