covered with plants that are growing thickly and in an uncontrolled way

The field is overgrown with weeds. 这片地里杂草丛生。

used to describe something that has grown too large

Cottonwood has become an overgrown town with inadequate facilities. 科顿伍德已经成了一个人口过多设施不足的镇子。

used to describe an adult who behaves like a child

They're acting like overgrown kids. 他们表现得就像是一群大孩子一样。

UK Jim is just an overgrown schoolboy. 吉姆不过是个大孩子。