못
cannot — inability, not by choice
Sits in front of the verb like 안, but says something different: not that you don’t, but that you can’t. English “didn’t” hides this distinction, so it has to be learned deliberately.
Build it
Pick a verb
When to use it
못 marks something as blocked — by circumstance, by lack of skill, by lack of time. 어제 못 갔어요 says you wanted to go and could not. Swap in 안 and you have said you chose not to, which may be an unintended insult.
Because it is about ability, 못 attaches only to action verbs. Adjectives describe states, and states cannot be prevented, so 못 좋아요 and 못 바빠요 do not exist. Use 안 with adjectives.
It splits 하다 verbs exactly as 안 does: 공부 못 했어요. One more thing to know is the pronunciation — 못 가요 sounds like [몯까요] and 못 해요 like [모태요], which is why it can be hard to catch in speech.
How to attach it
| Verb type | Form | Example |
|---|---|---|
| Action verb | 못 + verb | 못 가요 |
| Noun + 하다 | noun + 못 + 해요 | 공부 못 해요 |
| Adjectives | use 안 instead | 안 좋아요 — not 못 좋아요 |
| Longer alternative | -지 못하다 | 가지 못해요 |
| Similar meaning | -(으)ㄹ 수 없다 | 갈 수 없어요 |
| Pronunciation | assimilates | 못 가요 [몯까요], 못 해요 [모태요] |
In use
오늘은 시간이 없어서 못 가요.
I can’t go today because I don’t have time.
매운 음식을 못 먹어요.
I can’t eat spicy food.
어제는 잠을 못 잤어요.
I couldn’t sleep last night.
저는 노래를 못해요.
I’m not good at singing.
바빠서 연락 못 했어요.
I was busy, so I couldn’t get in touch.
아직 한국어를 잘 못해요.
I still can’t speak Korean well.
Compared with
안
안 is a choice; 못 is an obstacle. Declining an invitation with 안 갔어요 can sound like you did not want to come, so 못 갔어요 is the polite option when something got in the way.
파티에 안 갔어요. (I chose not to go) / 파티에 못 갔어요. (I couldn’t make it)
-지 못하다
The longer form of the same idea, preferred in writing and in more formal speech. The meaning is identical.
못 갔어요. (speech) / 가지 못했습니다. (writing)
-(으)ㄹ 수 없다
Also “cannot,” but it points at the impossibility itself rather than at a failed attempt. For a rule or a physical impossibility it is the more natural choice.
여기에서 담배를 피울 수 없어요. (it’s not allowed) / 어제 못 피웠어요. (I couldn’t manage to)
Watch out
시간이 없어서 못 공부했어요.
시간이 없어서 공부 못 했어요.
Noun + 하다 verbs split around 못, exactly as they do around 안. The same goes for 일 못 했어요 and 운동 못 했어요.
오늘 날씨가 못 좋아요.
오늘 날씨가 안 좋아요.
못 negates ability, and an adjective describes a state rather than an action. Adjectives always take 안.
아파서 학교에 안 갔어요. — meaning “I couldn’t go”
아파서 학교에 못 갔어요.
Being ill is an obstacle, not a decision. Using 안 here suggests you simply did not feel like going.
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