Saying No: 안, 못 and -지 않아요

Two kinds of "not"

English uses "don’t" for many situations. Korean separates two ideas.

안 means simple "not": you don’t do it, or you choose not to do it. It also works with adjectives: 안 비싸요 (it is not expensive).

못 means "cannot": you want to or try to, but something stops you. Maybe you have no time, no skill, or the situation does not allow it. 못 is used with verbs (actions), not with most adjectives.

Each one has a short form that goes before the verb, and a long form that goes after the stem. The meaning is the same; the long form sounds a little more formal or careful, and it is common in writing.

Where does 안 go with 하다 verbs?

Many verbs are made of a noun + 하다: 공부하다 (to study), 운동하다 (to exercise), 청소하다 (to clean). With these, the short negative goes between the noun and 하다: 공부 안 해요, 운동 못 해요.

If you put 안 at the very front, as in 안 공부해요, it sounds wrong to Korean ears. The long form avoids this problem: 공부하지 않아요, 운동하지 못해요.

But some 하다 words are adjectives or single words that cannot be split, such as 좋아하다 (to like) and 깨끗하다 (to be clean). For these, 안 goes in front: 안 좋아해요, 안 깨끗해요. When you are not sure, the long form -지 않아요 is always safe.

Two special verbs: 있다 and 알다

Some verbs have their own negative word instead of 안.

있다 → 없다. Instead of 안 있어요, say 없어요 (there isn’t / I don’t have). 시간이 없어요 means "I don’t have time."

알다 → 모르다. Instead of 안 알아요, say 몰라요 (I don’t know). This is one of the most useful words for learners: 잘 몰라요 (I don’t know well).

Also, for nouns with 이에요/예요, the negative is 아니에요: 학생이 아니에요 (I’m not a student).

잘 못 vs 잘못

In the dialogue you saw 잘 못 올라가요. 잘 못 + verb means "not good at doing it": 노래를 잘 못 해요 (I’m not good at singing). This is a modest and very natural thing to say.

Be careful with spacing: 잘못 written as one word is a different word meaning "mistake" or "wrongly". 제 잘못이에요 means "It’s my fault."