This is the 9784th most frequent Korean word.
고의로
Deliberately; intentionally.
The word '고의로' is used to convey that the action of leaving the door open was intentional.
그는 고의로 문을 열어 두었어요.
He intentionally left the door open.
Here, '고의로' emphasizes the speaker's intention to clarify that the statement was not deliberate.
나는 고의로 그런 말을 하지 않았어요.
I didn't intentionally say such a thing.
In this sentence, '고의로' is used to indicate that the mistake was not made with intent.