1. (Slang)쩐다 or 쩔어 means "Dope" or awesome in a positive way And can be used when someone is giving a sarcastic comment. E.g. when your room is dirty and your friend is laughing at you he can say your room is awesome ( even if he doesn't think so ) 2. (Slang) 절다 절었다 means you forget lyrics especially when you rap 3. 절다 which is often used as 쩔다 in a wrong way mean to 1. be salted 2. To has sweated a lot 3. To be drunk a lot E.g. 1. 배추를 소금에 절었다 the cabbage has been salted 2. 땀에 절(쩔)었다 he has sweated a lot ( he is soaked in sweat 3. 술에 절(쩔)어있다 he has been drunk ㅡㅡㅡㅡㅡㅡㅡ 4. 다리를 절다 means to limp

I've never heard someone uses it in a negative way. Most of the time, it means "super awesome," or "so cool," like '대박(You might have heard of this expression),' but '쩔다/쩐다' is a slang (kind of). So I recommend you do not use it to people whom you are not that close.

'쩔다'처럼 쓰일 수 있는 표현은 아주 많아요. 상황에 따라서, 말하는 사람의 억양에 따라서 판단해야 할 것 같아요. ^^; 본래의 뜻은 긍정이지만 비꼬기 위해서 일부러 그렇게 표현하는 것이니까요... 예) 엄마: 숙제를 다 했구나. 아주 잘 한다.(칭찬의 말) 엄마: 숙제를 하나도 안 했구나. 아주 잘 한다.(비난의 말) - 억양이 다름.