3 Words in Running Man 310(대표 선발 레이스 , Representative Player Contest Race)
국가대표 is a member of the national team. 국가 means nation and 대표 means representative. So, it means a athlete who represents a nation.
When you become a 국가대표, it is 국가대표가 되다. However, you can sometimes find some expressions like "태극 마크를 달다". 국가대표s have a small national flag on their uniforms. In Korean flag, the blue and red circle is called 태극 무늬. So, it is a 태극 마크.
Sometimes, 국가대표 is used to call someone who is really good at something. It's natural that those athletes should be really good to be in national teams. You can use this style of writing in other fields like writing, baking, etc.
이거 완전 국가대표급 요리실력인데?
You are so good at cooking.
항상 태극 마크를 달고 싶다는 꿈이 있었는데, 그 꿈을 10년이나 지나서 이루게 되었다.
He always wanted to be a player in the national team. His dream came true after 10 years.
막장 originally means the end in the mine gallery. 막장 is deep inside and it is really dangerous. It is possible that the roof of the mine can fall and he/she entered there cannot go out. Because of that, no one wants to go in there. However, the payment is really good.
So, if someone goes there to earn money, his life is not in a good state. He's really desperate to earn money. From this, 막장 describes something which became the worst or as bad as possible.
If some drama is 막장, it means that the story arc became as immoral as possible. These dramas have kills, divorce, kids from other wives, etc. The story is really bad and predictable, but sadly, these dramas have good rates(시청률).
인생 막장도 아니고 왜 그렇게 사는 건데?
Your life isn't ended. Why are you living like that?
막장 드라마에 한 번 빠지면 못 빠져나와.
If you are into an immoral drama, you cannot come out.
금단 현상 is withdrawal symptoms. When you stop smoking, you can experience symptoms like yawns, insomnia, pains, anxiety, etc.
Sometimes, Korean use this word to describe the situation when you cannot stop something. In the screenshot above, the members cannot simply stop singing. So, the editor used this word.
담배 끊고 금단 현상 때문에 몇 달 간 고생했다.
After stopping smoking, I had a hard time for a few months because of withdrawal symptoms.
공부 그만한다고 금단 현상이 오는 것은 세상에 너밖에 없을 거다.
It might be only you in the world who suffer from withdrawal symptoms because of stopping study.