Difference between to not know and to forget in Korean

모르다·잊어버리다

to not know

모르다to not know

모르다 means "to not know" or "to be unaware." Use it when you do not know a fact, a person, an answer, or how to do something. In daily conversation, you will often hear the polite form "몰라요" for "I don't know."

How to say to not know
to forget

잊어버리다to forget

'잊어버리다' means to forget something. You use it when you do not remember something, or when you leave something behind by accident. It is common in daily life for things like homework, names, keys, or plans.

How to say to forget

The difference

모르다 means you do not know something in the first place. 잊어버리다 means you knew it before, but then you forgot it.