Difference between to not know and to lack in Korean

모르다·모자라다

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 lack — 모자라다to lack
모자라다 means there is less than you need. People use it for things like money, time, food, seats, and supplies. In everyday speech, it often means “not enough” or “short of something.”
How to say to lack

The difference

모르다 means you do not know a fact, answer, or person. 모자라다 means something is short or insufficient.