Key Facts
- Hangul: 멍청하다 (meongcheonghada)
- Meaning: stupid
- Level: B1
- Part of speech: adjective
- Stem: 멍청하
- Conjugation class: 하다 type
- Grammar: Judges intelligence; the person takes 이/가 or 은/는.
- Usage: Insulting if aimed at others, so usually said about yourself.
What Does 멍청하다 Mean?
멍청하다 describes someone who is dull, foolish or acts without thinking, as in 멍청한 실수 (a stupid mistake). It is a judgement about intelligence, not just a slip.
Aimed at another person it is insulting. Learners mostly use it about themselves, as in 제가 멍청했어요. It is informal, and the related 바보 (fool) is even more common.
How Do You Pronounce 멍청하다?
The dictionary form is read as spelled, with the plain ㅇ endings of 멍 and 청 flowing into 하다. The formal present 멍청합니다 is [멍청함니다] and the formal past is [멍청핻씀니다].
How Do You Use 멍청하다 in a Sentence?
제가 정말 멍청했어요.
I was really stupid.
제가 stresses that the speaker is the one who was foolish; the past 멍청했어요 admits a mistake.
멍청한 실수를 했어요.
I made a stupid mistake.
멍청한 comes before 실수를, and 했어요 turns 'mistake' into 'made a mistake'.
저는 멍청하지 않아요.
I am not stupid.
저는 멍청하지 않아요 is a defensive denial, so use it with care.
How Does Meongcheonghada Conjugation Work?
멍청하다 is a 하다 adjective: 멍청해요, 멍청했어요, 멍청해서. The modifier is 멍청한, and the negative is 멍청하지 않아요. The honorific 멍청하세요 is grammatical, but it would insult anyone you respect.
멍청하다
| Form | Korean | Romanization | Rule |
|---|---|---|---|
| Polite present | 멍청해요 | ||
| Polite past | 멍청했어요 | ||
| Polite future (plan) | 멍청할 거예요 | ||
| Polite future (intention or guess) | 멍청하겠어요 | ||
| Formal present | 멍청합니다 | ||
| Formal past | 멍청했습니다 | ||
| Formal future | 멍청할 것입니다 | ||
| Casual present | 멍청해 | ||
| Casual past | 멍청했어 | ||
| Casual future | 멍청할 거야 | ||
| Honorific polite | 멍청하세요 | ||
| Because / and then | 멍청해서 | ||
| If (conditional) | 멍청하면 | ||
| Present modifier (before a noun) | 멍청한 | ||
| Past modifier (before a noun) | 멍청했던 | ||
| Future modifier (before a noun) | 멍청할 | ||
| Negative with 안 (short) | 안 멍청해요 | ||
| Negative (long form) | 멍청하지 않아요 |
No want-to row: -고 싶다 suits verbs.
Sound Changes
| Form | Korean | Sounds like |
|---|---|---|
| Polite past | 멍청했어요 | [멍청해써요] |
| Polite future | 멍청할 거예요 | [멍청할꺼예요] |
| Polite future guess | 멍청하겠어요 | [멍청하게써요] |
| Formal present | 멍청합니다 | [멍청함니다] |
| Formal past | 멍청했습니다 | [멍청핻씀니다] |
| Formal future | 멍청할 것입니다 | [멍청할꺼심니다] |
| Casual past | 멍청했어 | [멍청해써] |
| Casual future | 멍청할 거야 | [멍청할꺼야] |
| Past modifier | 멍청했던 | [멍청핻떤] |
| Long negative | 멍청하지 않아요 | [멍청하지 아나요] |
멍청하다 Forms to Reach for First
- Politely (stupid): 멍청해요
- Earlier, in the past (stupid): 멍청했어요
- Giving the reason (stupid): 멍청해서
- If the condition holds (stupid): 멍청하면
- Before a noun (stupid): 멍청한, or 멍청했던 for the past
- Denying it (stupid): 멍청하지 않아요
- Honorific, about a respected person (stupid): 멍청하세요
Common Mistake
Wrong: ✗ 멍청하는 실수
Correct: ✓ 멍청한 실수
Why: 멍청하다 is an adjective, so before a noun it takes -한: 멍청한 실수 is a stupid mistake. The -하는 ending is for verbs. Mind the register too: 선생님은 멍청하세요 is grammatical but very rude, so keep the word for yourself (제가 멍청했어요) or close friends.
When Does 멍청하다 Fit Best?
Use 멍청하다 for self-criticism or a close friend's joking. Avoid it for anyone you do not know well.
What Is Easy to Confuse with 멍청하다?
| Word | How to tell it from 멍청하다 |
|---|---|
| 똑똑하다 | The opposite: 똑똑하다 means smart, while 멍청하다 means dull and foolish. |
| 이상하다 | 이상하다 means strange or odd; 멍청하다 is a judgment about intelligence and is much harsher. |
Forgetting a Ticket at Home
Two friends have reached the cinema. Alex discovers that the ticket is at home and criticizes the mistake. Jisu responds without agreeing with that harsh judgment.
Alex
표를 집에 두고 왔어요. 제가 멍청했어요.
Pyoreul jibe dugo wasseoyo. Jega meongcheonghaesseoyo.
I left the ticket at home. That was stupid of me.
Jisu
멍청한 실수는 아니에요.
Meongcheonghan silsuneun anieyo.
It isn’t a stupid mistake.
Alex
그래도 저는 멍청한 실수를 한 것 같아요.
Geuraedo jeoneun meongcheonghan silsureul han geot gatayo.
Still, I think I made a stupid mistake.
Jisu
괜찮아요. 휴대폰으로 표를 찾아봐요.
Gwaenchanayo. Hyudaeponeuro pyoreul chajabwayo.
It’s okay. Let’s look for the ticket on your phone.
멍청했어요 looks back at Alex’s action, while 멍청한 labels the mistake before the noun 실수. Jisu avoids repeating the insult as a description of Alex. The final suggestion moves the conversation toward solving the ticket problem.
Collocations: a Mistake, a Question or a Person?
멍청한 실수 is “a stupid mistake”. Speakers use it when an error seems avoidable, such as bringing the wrong ticket or forgetting a simple instruction. The adjective adds self-criticism; 실수 alone already means “mistake”. You can remove 멍청한 without losing the basic information about what happened.
멍청한 질문 means “a stupid question”. It may appear when someone apologizes before asking something they fear is obvious. Calling another person’s question this can shut down a conversation. The phrase judges the question, but its effect can still feel personal to the person who asked it.
멍청한 짓 means “a stupid thing to do” or “a foolish act”. 짓 points to conduct and often carries disapproval. This pairing focuses on a particular action. It is still harsh, especially when you use it about someone else’s decision in front of other people.
None of these combinations is a hidden idiom: the adjective keeps its meaning of foolish or stupid. The noun tells you whether the criticism targets an error, a question or an action. That small noun matters when translating dialogue into natural English.
Where Will You Hear 멍청하다, and How Strong Is It?
In a drama argument, 멍청해 can be a direct insult. In a scene where someone has lost their keys, the same form may be frustrated self-talk. Check who the speaker is describing before deciding whether an English subtitle should say “you’re stupid” or “that was stupid of me”. Korean often leaves the subject unstated.
The ending 요 makes 멍청해요 polite in sentence style. It does not make a judgment about someone’s intelligence kind. The formal 멍청합니다 is possible in grammar, but its formal ending does not remove the insult either. A table of forms shows what can be built; the relationship and situation determine what fits.
Self-deprecating use can also invite reassurance. If a friend says 제가 멍청했어요, they may be expressing embarrassment about one incident rather than asking you to assess their intelligence. A response such as the dialogue’s 괜찮아요, “it’s okay”, acknowledges the feeling without endorsing the label.
멍청하다 and 멍하다 also deserve separate attention. 멍하다 can describe looking blank or being dazed. Someone who is tired may stare into space without being foolish. The shared opening sound does not make the two adjectives identical, so use the whole word and the situation to identify the meaning.
What Related Words Help You Describe the Situation Precisely?
| Korean | Meaning | One useful distinction |
|---|---|---|
| 실수 | mistake | Names the error without judging intelligence. |
| 바보 | fool | A noun; its warmth or harshness depends on the relationship and tone. |
| 똑똑하다 | to be smart | Praises intelligence rather than politeness. |
| 무례하다 | to be rude | Describes disrespectful conduct rather than lack of intelligence. |
The personality and appearance vocabulary gives a wider set for describing people. Choose a behavior word when the problem is how someone acted toward you.
Mini Drill: Describe the Error
- Change 멍청하다 to the polite past for a mistake you just made.
- Complete “a stupid mistake”: ____ 실수.
- Use the long negative to say “I’m not stupid”.
- Does 멍청하세요 become a respectful compliment because it has 세요?
Show drill answers
- 멍청했어요.
- 멍청한 실수. This adjective uses 한 before the noun.
- 저는 멍청하지 않아요.
- No. The ending cannot turn an insulting meaning into praise.
Quick Self-Test
- Which word names a mistake without adding “stupid”?
- Does 멍청해 always describe the listener?
- Which word means rude: 멍청하다 or 무례하다?
Show answers
- 실수.
- No. The subject may be the speaker or someone else in context.
- 무례하다 describes rude behavior.
Frequently Asked Questions
What Is the Polite Present of 멍청하다?
멍청해요.
Is 멍청하다 Rude?
Yes, when aimed at someone else. About yourself it is self-deprecating.
What Is the Difference from 이상하다?
이상하다 means strange or odd; 멍청하다 judges intelligence and is much harsher.
What Is the Opposite?
똑똑하다, meaning smart.
Which Words Are Related to 멍청하다?
What Should You Learn Next?
Compare 멍청하다 with 똑똑하다 and 영리하다, then read 무례하다 to see how Korean describes rude behaviour. The pattern is explained in how 하다 words become 해요. Then run another word through the Korean verb conjugator or browse the Korean verb dictionary.