septuagenarian
🇺🇸
/ˌseptʃuədʒəˈneriən/
🇬🇧
/ˌseptjuədʒəˈneəriən/
A person who is between 70 and 79 years old.
My grandfather is a healthy septuagenarian who still enjoys hiking.
我的祖父是一位健康的七旬老人,仍然喜欢徒步旅行。