This is the 12990th most frequent Korean word.
돌이킬
"돌이킬" means "to reverse" or "to turn back."
Here, '돌이킬' refers to reversing or undoing the spoken words.
그가 한 말은 이제 돌이킬 수 없어.
The words he said cannot be taken back now.
In this context, '돌이킬' signifies irreversibility in the state of friendship.
우리의 우정을 돌이킬 수 없는 쪽으로 가버렸어.
Our friendship has moved in an irreversible direction.
Here, '돌이킬' is used to imply pperhaps reversing or changing historical events.