젠장, 망할, 제길 and 제기랄 Only 망할 is clear in meaning. 망하다 = be ruined; go bust; fail; go bankrupt. It's used like 망할 것, 망할 자식, 망할 놈의 + NOUN, etc. It is not a bad word at all in and of itself, but can be used with one like 놈, 자식, 새끼, etc. The others are used as strong expletives with no special meaning (제길 and 제기랄 are variations of the same phrase) - they are all old words not used very often nowadays.