Side by side
안 vs 못: Won't or Can't?
One says you chose not to. The other says something stopped you.
Both 안 and 못 sit in front of a verb and make it negative, so beginners often treat them as interchangeable. They are not, and the difference is one English speakers care about too.
술을 안 마셔요 means 'I don't drink': a choice you have made. 술을 못 마셔요 means 'I can't drink': an allergy, medication, a low tolerance, something outside your control. Using the wrong one can make you sound either rude or strangely helpless.
In one line
안 = you choose not to. 못 = you would, but you are unable to.
| Particle | Core meaning | Used with | Example |
|---|---|---|---|
| 안 (an) | Simple negation / choice | Verbs and adjectives | 안 갔어요 an gasseoyo I didn't go (I chose not to) |
| 못 (mot) | Inability / prevented | Verbs only, never adjectives | 못 갔어요 mot gasseoyo I couldn't go (something stopped me) |
When to Use 안
1. A Decision You Made
안 is plain negation. It states that the action simply does not happen, usually because you decided so. It is the default negative in Korean.
저는 고기를 안 먹어요.
jeoneun gogireul an meogeoyo.
I don't eat meat.
2. With Adjectives
Only 안 can negate an adjective. Since 못 is about ability, and a quality has no ability, 못 예뻐요 is impossible.
오늘은 안 추워요.
oneureun an chuwoyo.
It isn't cold today.
3. The Long Form: 지 않다
지 않다 is the formal written equivalent of 안, with exactly the same meaning. 안 먹어요 and 먹지 않아요 are interchangeable in meaning; the second is simply more formal.
그는 담배를 피우지 않습니다.
geuneun dambaereul piuji anseumnida.
He does not smoke.
When to Use 못
Use 못 when you want to do something but cannot. The obstacle can be a skill you lack, a physical limit, no time, no money, or a rule. Because it is entirely about ability, 못 never attaches to adjectives. Its formal long form is Stem + 지 못하다.
배가 아파서 밥을 못 먹었어요.
baega apaseo babeul mot meogeosseoyo.
I couldn't eat because my stomach hurt.
저는 수영을 못해요.
jeoneun suyeongeul motaeyo.
I can't swim.
약속을 지키지 못했습니다.
yaksogeul jikiji motaetseumnida.
I was unable to keep my promise.
The core difference
Choice
“You decided not to”
Inability
“Something is in the way”
Common mistakes
저는 안 예뻐요 / 저는 못 예뻐요
jeoneun an yeppeoyo / jeoneun mot yeppeoyo
저는 안 예뻐요
jeoneun an yeppeoyo
예쁘다 is an adjective. Adjectives describe a quality, not an ability, so they can only take 안.
못 공부해요
mot gongbuhaeyo
공부 못 해요
gongbu mot haeyo
With 하다 verbs, 못 splits the word and goes directly before 해요. The same applies to 안: 공부 안 해요.
시험에 떨어져서 안 갔어요
siheome tteoreojyeoseo an gasseoyo
시험에 떨어져서 못 갔어요
siheome tteoreojyeoseo mot gasseoyo
Failing the exam is an obstacle, not a preference. When an outside cause blocks you, use 못.
저는 술을 못 마셔요 (when you simply prefer not to)
jeoneun sureul mot masyeoyo
저는 술을 안 마셔요 (O)
Saying 못 implies you physically cannot. If you are just declining, 안 is the honest choice, though Koreans do sometimes use 못 as a polite way to refuse without explaining.
못 알아요
mot arayo
몰라요
mollayo
A few verbs have their own negative forms and reject 못 entirely: 알다 becomes 모르다, and 있다 becomes 없다.
How to Choose in 5 Seconds
Ask these in order and stop at the first yes.
Frequently asked questions
How is 못 pronounced?
The final consonant becomes [ㄷ], and it then assimilates to the next word. 못 해요 sounds like [모태요], 못 먹어요 like [몬머거요], and 못 가요 like [몯까요]. Koreans rarely pronounce it as a clean, separate 못.
What is the difference between 못 하다 and 못하다?
Spaced, 못 하다 means 'cannot do it'. Written together, 못하다 means 'to be bad at it'. 노래를 못 해요 = I can't sing right now. 노래를 못해요 = I sing badly.
Can 안 and 못 both appear with 지 forms?
Yes. 안 pairs with 지 않다 and 못 pairs with 지 못하다. Both long forms are more formal and are what you will see in writing and news.
Is using 못 ever considered impolite?
The opposite: it is often the polite option. Turning down an invitation with 못 가요 ('I can't go') sounds softer than 안 가요 ('I'm not going'), because it implies circumstances rather than disinterest.
Look them up in the dictionary
Both particles in the Basic Korean Dictionary from the National Institute of Korean Language, with English.