This is the 5717th most frequent Korean word.
버린
"버린" means "discarded" or "abandoned."
Here, '버린' is used as part of '잃어버린', indicating a completed action or regret of losing something.
나는 책을 잃어버린 것 같아.
I think I lost the book.
In this sentence, '버린' in '끝내버린' emphasizes the decisiveness or finality of completing the work.
그는 갑자기 일을 끝내버린 후 떠났다.
He suddenly finished the work completely and left.
The use of '버린' in '망쳐버린' conveys a sense of irreversibility and regret in ruining the plan.