เด็กเจ็ดเข้าเฒ่าเจ็ดสิบ

Etymology
From ; literally "a seven-year-old child, a seventy-year-old senile".

Noun

 * 1)  a person whose legal capacity is limited or who is placed under guardianship, especially because of age, as a minor, a person affected by senility, etc.