When to use young man in Korean
Korean: 청년[ cheong-nyeon ]

When to use it
The word "청년" means a young man. It usually talks about an adult man who is still young, often in his late teens, twenties, or thirties. People use it when describing someone in a simple, general way.
Example sentences
우리 형은 키가 큰 청년입니다.
My older brother is a tall young man.
학교 앞에 한 청년이 서 있어요.
A young man is standing in front of the school.
그 청년은 엄마를 도와줘요.
That young man helps my mom.
가게에서 청년이 우유를 사요.
A young man buys milk at the store.
버스에서 한 청년이 자리를 양보했어요.
A young man gave up his seat on the bus.
공원에서 청년들이 축구를 해요.
Young men are playing soccer in the park.