못 negation (cannot, unable to)

Using 못 is actually quite simple, but it has two main styles. We call them the "Short Form" and the "Long Form." The Short Form is the cool, casual version you’ll hear everywhere in daily conversation. You just take the word 못 and plop it right before your verb. It’s like adding a "no" sticker to a box. The Long Form, which uses the ending -지 못하다, is a bit more formal and carries a slightly heavier weight. It’s like saying "I am in a state of being unable to." Both mean roughly the same thing, but you’ll use the short version 90% of the time when talking to friends. Just remember: 못 is an adverb. It needs a verb to follow it. It can't stand alone and look pretty. It needs to work with an action to make sense. If you just say 못!, people will look at you like you’ve forgotten the rest of your sentence.

1. 1Let’s break down the steps to build these sentences. It’s as easy as making instant ramen.
2. 2For the Short Form: Simply put 못 before the verb.
3. 3가요 (go) becomes 못 가요 (cannot go).
4. 4먹어요 (eat) becomes 못 먹어요 (cannot eat).
5. 5Crucial Rule: Always put a space after 못 when it's the adverb! If you don't, the grammar police might not arrest you, but it’ll look messy.
6. 6For 하다 Verbs: This is where it gets spicy. For verbs that look like Noun + 하다 (like 공부하다 or 수영하다), 못 likes to jump into the middle.
7. 7공부하다 (to study) becomes 공부 못해요 (cannot study).
8. 8운전하다 (to drive) becomes 운전 못해요 (cannot drive).
9. 9Think of 하다 as the bodyguard; 못 has to slip past the noun to get to the action.
10. 10For the Long Form: Attach -지 못하다 to the verb stem.
11. 11Take 가다 (to go), drop the 다, and add -지 못해요.
12. 12Result: 가지 못해요.
13. 13This form works for all verbs, including those tricky 하다 ones, without needing to split them. 공부하지 못해요 is perfectly fine!

You use 못 whenever there is a wall between you and the action you want to do. Let’s look at the three main scenarios:

• Lack of Ability: You simply don't have the skill yet. Maybe you haven't learned how to swim (수영 못해요) or you don't know how to drive a manual car. It’s not that you refuse to do it; you just lack the "software" in your brain or the "hardware" in your muscles.
• External Circumstances: This is the "life happened" category. You wanted to go to the party, but you had too much homework. You want to buy the shoes, but the store is closed. Here, 못 explains that the world is stopping you.
• Physical or Mental State: You’re too tired to study, or you’re so sick you can’t eat. Even if you have the skill and the opportunity, your body is saying "not today, buddy."

This is where things can get a bit awkward if you aren't careful.

• Adjectives: Generally, 못 is for actions. You can't say 못 예뻐요 to mean "cannot be pretty." That doesn't even make sense! (And you're always pretty anyway). For adjectives, we usually use 안 or other negative forms.
• Intentional Refusal: If you’re on a diet and refuse to eat cake, use 안 먹어요. If you use 못 먹어요, your friends will think you have a gluten allergy and might start worrying. Be clear about whether it's your choice or a limitation.
• Special Verbs: Some verbs have their own secret negative versions. Instead of 못 알아요, we almost always use 몰라요 (don't know). Using 못 알아요 sounds a bit like your brain has a mechanical failure, which is a bit dramatic for a casual chat.

Yes, even native speakers mess this up sometimes (especially the spacing!), so don't sweat it. The biggest slip-up is the 안 vs 못 confusion. If you say 숙제 못 했어요 (I couldn't do my homework), your teacher might be sympathetic because your internet went out. If you say 숙제 안 했어요 (I didn't do my homework), you're basically admitting you chose to watch Netflix instead. Another classic mistake is the "Spacing Sin." Remember: 못 [Space] Verb. If you write 못가요, it’s technically a spelling error. Lastly, don't forget the 하다 split. Saying 못 공부해요 sounds very "foreigner-style." While people will understand you, splitting it to 공부 못해요 makes you sound like a pro who has lived in Seoul for years.

You might have seen -을 수 없다. Both mean "cannot," so what’s the deal? Think of 못 as the quick, punchy, conversational way to say it. It’s the "I can't" of the Korean world. -을 수 없다 is more about "possibility" or "capability." It’s a bit more formal and literal. If you’re at a dinner table and someone offers you spicy food, 못 먹어요 is the natural response. -을 수 없습니다 sounds like you’re reading from a medical report. Also, 못 often implies a specific, temporary situation, while -을 수 없다 can feel more like a permanent state or a formal rule. It’s like the difference between "I can't come today" and "It is not possible for me to attend."