Lesson 15 · 안 / -지 않아요 & 못 / -지 못해요
Hyeju’s Beginner Korean Grammar Class · Lesson 15
안 / -지 않아요
못 / -지 못해요
Separate simple negation from inability and blocked actions.
“Do Not” or “Cannot”?
안 simply negates the action; context may suggest a choice or habit. 못 highlights inability or something preventing the action. 안 does not always mean refusal, and 못 does not only mean lack of skill.
Today’s Grammar
V/A stem + 지 않아요
못 + V
V stem + 지 못해요
V = verb, A = descriptive verb (adjective). A stem is the dictionary form without 다: 먹다 → 먹-, 공부하다 → 공부하-. The long negative attaches to that stem, not to the already-conjugated polite form.
Part 1 · 안 / -지 않아요
Use 안 before a suitable conjugated predicate. Or attach -지 않아요 to the stem. These usually express the same basic negative idea, with differences in emphasis and context.
For nouns, use 아니에요: 저는 학생이 아니에요. For existence or possession, use 없어요: 책이 없어요. Do not mechanically add 안 to every Korean predicate.
Part 2 · 못 / -지 못해요
Use these beginner patterns with action verbs when skill, opportunity, or circumstances prevent an action.
The reason can be a busy schedule, an injury, unavailable transport, or missing skill. Do not use 못 as the basic negative for ordinary adjectives such as 비싸요; practice 안 비싸요 / 비싸지 않아요 instead.
Part 3 · Common Activity Noun + 하다 Verbs
| Positive | Simple negative | Cannot |
|---|---|---|
| 공부해요 | 공부를 안 해요 / 공부하지 않아요 | 공부를 못 해요 / 공부하지 못해요 |
| 운동해요 | 운동을 안 해요 / 운동하지 않아요 | 운동을 못 해요 / 운동하지 못해요 |
For these activity nouns, put 안 or 못 before 해요: 공부를 안 해요, 운동을 못 해요. The noun marker 를/을 is often omitted in conversation: 공부 안 해요. Do not teach “안 + any whole word” as a universal rule.
Mini Dialogue
A: 오늘 공원에 가요?
oneul gongwon-e gayo · Are you going to the park today?
B: 아니요. 오늘 못 가요.
aniyo. oneul mot gayo · No. I cannot go today.
A: 바빠요?
bappayo · Are you busy?
B: 네. 오늘은 일해요.
ne. oneureun ilhaeyo · Yes. Today I work.
바빠요 means “busy.” The dialogue supplies the situation, so 못 가요 is an inability to go today, not an inability to walk.
Compare with similar grammar
LESSON 35
-지 마세요
여기에 들어가지 마세요.To tell someone not to do something, use -지 마세요, not 안.
Look ahead: Lesson 35 →LESSON 38
-(으)ㄹ 수 없어요
지금은 전화를 받을 수 없어요.Like 못, it means “can’t”, and often sounds a little more formal or about circumstances.
Look ahead: Lesson 38 →| Pattern | Meaning | Short form | Long form |
|---|---|---|---|
| 안 | don’t / won’t (choice) | 안 가요 | 가지 않아요 |
| 못 | can’t (ability, circumstances) | 못 가요 | 가지 못해요 |
| 아니에요 | is not (nouns) | — | 학생이 아니에요 |
Common mistakes
마셔지 않아요 → 마시지 않아요: attach 지 to 마시-, the stem.
저는 안 학생이에요 → 저는 학생이 아니에요: nouns use 아니에요.
이 가방은 못 비싸요 → For this ordinary adjective negative, 이 가방은 안 비싸요.
Keep short negative adverbs separate: 안 가요, 못 가요. In the long negative, write 가지 않아요 / 가지 못해요. The spelling of the separate verb 못하다 has additional meanings; it is not needed for today’s basic practice.
With noun + 하다 verbs, 안 and 못 go right before 하다.
If you lack the ability, use 못. 안 sounds like you choose not to.
Nouns take 아니에요.
The long negative is -지 않아요 (from 않다), not 안 해요.
Mini practice · six questions
All sentences below are new. Try each one before opening the answer.
- Fill in the blank저는 채식주의자예요. 고기를 ___ 먹어요.
Check answer
저는 채식주의자예요. 고기를 안 먹어요.
You choose not to eat meat, so use 안.
- Fill in the blank · long form오늘은 날씨가 ______. (춥다)
Check answer
오늘은 날씨가 춥지 않아요.
춥 + 지 않아요 → 춥지 않아요. “It isn’t cold today.”
- Choose the better form다리를 다쳤어요. 그래서 오늘은 축구를 (안 / 못) 해요.
Check answer
못
You’re hurt, so you can’t play: 못.
- Choose the better form저는 커피를 안 좋아해요. 그래서 커피를 (안 / 못) 마셔요.
Check answer
안
You don’t like it, so you choose not to drink it: 안.
- Find and fix the mistake주말에는 안 공부해요.
Check answer
주말에는 공부 안 해요.
공부하다 is noun + 하다, so 안 goes before 하다: 공부 안 해요.
- Say it in KoreanI can’t speak Japanese.
Check answer
저는 일본어를 못해요.
It’s about ability, so use 못. 일본어를 할 수 없어요 is also correct.
Today’s Key Point
안 / -지 않아요 → simple negation.
못 / -지 못해요 → inability or a preventing situation.
Activity noun + 하다: 공부를 안 해요; 운동을 못 해요.
Reference
Usage checks: National Institute of Korean Language · short and long negation; 못 negation and spacing. Lesson examples are original.
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