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믿을 수 없다

A2 adjective 8 min read

믿을 수 없다

mideul su eopda

Practice it Examples Notes & Tips 믿을 수 없다 in 30 Seconds

Explanation 믿을 수 없다 in your Level:

At the A1 level, you should learn '믿을 수 없다' as a set phrase for shock. Think of it like saying 'No way!' or 'Really?' when a friend tells you something surprising. You don't need to worry about the complex grammar yet. Just remember that '믿을 수 없어!' is what you say when you are surprised. For example, if you see a very cheap phone, you can say '믿을 수 없어!' because the price is so low. It is a great way to show emotion in basic conversations. You will mostly use it at the end of a sentence. It helps you sound more natural when reacting to news. Start by practicing the short form with your friends. It is one of the most common ways to show you are listening and interested in what they are saying.

At the A2 level, you start to see how this phrase is built. It comes from '믿다' (to believe) and '-(으)ㄹ 수 없다' (cannot). You can use it to describe things that are 'unbelievable.' For example, '믿을 수 없는 가격' means 'an unbelievable price.' At this level, you should also learn that it can describe a person who is not reliable. If someone always lies, they are '믿을 수 없는 사람.' You should practice conjugating it into the polite form '믿을 수 없어요' for daily use. You will also begin to see it in simple stories or news clips. It is important to distinguish between using it for a 'good' surprise and a 'bad' lack of trust. This dual meaning is very common in Korean, and mastering it helps you move toward intermediate fluency.

At the B1 level, you should be comfortable using '믿을 수 없다' in various sentence structures. You will learn to use it with more complex subjects, like '그가 그런 말을 했다는 사실을 믿을 수 없다' (I can't believe the fact that he said such a thing). You should also start using related words like '신뢰' (trust) and '의심' (doubt) to explain *why* something is unbelievable. At this stage, you should understand the nuance of using this phrase in a professional versus personal context. In a professional setting, saying '믿을 수 없습니다' about a report suggests it lacks data or logic. In a personal setting, it suggests emotional shock. You should also be able to use the modifier form '-는' correctly in longer sentences to describe complex situations, such as '믿을 수 없는 일이 벌어졌다' (An unbelievable thing occurred).

At the B2 level, you should explore the idiomatic uses of '믿을 수 없다.' This includes phrases like '눈을 믿을 수 없다' (cannot believe one's eyes). You should be able to discuss the concept of 'trust' (신용, 신뢰) in Korean society and how '믿을 수 없다' reflects a breach of social contracts. You will also encounter this phrase in more formal literature and news editorials where it might be used to criticize a policy or a social phenomenon. You should understand how it differs from '믿기지 않다' (to not be believed), which is a passive form often used to describe a surreal feeling. At B2, your usage should reflect an understanding of the emotional weight the phrase carries, and you should be able to use it to express skepticism in a nuanced way during debates or discussions.

At the C1 level, you should analyze '믿을 수 없다' within the broader context of Korean linguistics and psychology. This involves understanding the 'prospective' nature of the '-을' modifier and how it implies a potentiality that is being denied. You should be able to use the phrase in high-level writing to express profound existential or philosophical disbelief. You will also study how this phrase is used in legal or historical texts to describe events that were considered 'unthinkable' or 'unprecedented.' Your ability to switch between '믿을 수 없다,' '불신하다,' '회의적이다' (to be skeptical), and '가당치 않다' (to be absurd) should be seamless, choosing the exact word that fits the register and the specific type of disbelief you wish to convey. You should also be able to interpret the cultural implications of 'untrustworthiness' in a society that values collective integrity.

At the C2 level, you have a masterly command of '믿을 수 없다' and its role in the Korean language's expressive palette. You can dissect the phrase's evolution and its usage in classical versus modern literature. You understand the subtle prosodic features—the intonation and stress—that change the meaning from a simple exclamation to a profound condemnation of character. You can use it to craft sophisticated rhetoric, perhaps in a speech or a formal essay, where the phrase serves as a powerful stylistic tool to emphasize the absurdity or the gravity of a situation. You are also aware of how the phrase interacts with other complex grammatical structures, such as double negatives or rhetorical questions, to create layers of meaning. At this level, the phrase is not just a vocabulary item but a flexible instrument for nuanced communication.

Practice it Examples Notes & Tips

믿을 수 없다 in 30 Seconds

Used to express shock or surprise ('I can't believe it!').
Used to describe an untrustworthy person or thing ('unreliable').
Commonly used in idioms like 'cannot believe one's eyes'.
Follows the '-(으)ㄹ 수 없다' grammar pattern for impossibility.

The Korean phrase 믿을 수 없다 (mideul su eopda) is a multifaceted expression that bridges the gap between simple disbelief and a deep-seated lack of trust. At its core, it is composed of the verb 믿다 (to believe/trust), the prospective modifier -을, the bound noun 수 (possibility/way), and the negative existential verb 없다 (to not exist). Together, they literally translate to 'the possibility of believing does not exist.' However, in practical usage, its meaning shifts depending on the context, ranging from 'I am shocked' to 'That person is dishonest.'

The Nuance of Shock: In many situations, this phrase is used as an exclamation of surprise. When something extraordinary happens—whether good or bad—Koreans will say '믿을 수 없어!' to mean 'I can't believe it!' It is equivalent to the English 'Unbelievable!' or 'Incredible!' in this sense.

이게 정말 사실인가요? 정말 믿을 수 없다!

Is this really true? I really can't believe it!

The Nuance of Character: When applied to a person or a source of information, it takes on a more critical tone. It describes someone who is unreliable, untrustworthy, or shady. If you say '그 남자는 믿을 수 없는 사람이에요,' you are warning someone that the man is not dependable or might be a liar.

In Korean society, trust is a cornerstone of interpersonal relationships. Because of the emphasis on 'Jeong' (social bonding) and collective harmony, labeling someone as '믿을 수 없다' is a significant social judgment. It suggests a break in the expected sincerity that governs social interactions. You will often hear this in K-dramas during scenes of betrayal, or in news reports discussing fraudulent schemes or political scandals where public trust has been violated.

그의 약속은 믿을 수 없다.

His promises are unreliable (cannot be trusted).

Furthermore, the phrase is frequently used in the context of sensory disbelief. Phrases like '눈을 믿을 수 없다' (cannot believe one's eyes) or '귀를 믿을 수 없다' (cannot believe one's ears) are standard ways to express that what one is witnessing or hearing is so out of the ordinary that it defies logic. This usage mirrors English idioms closely, making it an easy bridge for English speakers to cross when learning emotive Korean.

Using 믿을 수 없다 correctly requires an understanding of Korean sentence structure and the way adjectives (or descriptive phrases) modify nouns. Since it ends in 없다, it follows the conjugation patterns of existential verbs. In its base form, it is '믿을 수 없다,' but in polite conversation, you must conjugate it to 믿을 수 없어요 or 믿을 수 없습니다.

As a Predicate: When placed at the end of a sentence, it describes the subject. For example, '결과를 믿을 수 없어요' (I can't believe the results). Here, the focus is on the speaker's state of disbelief regarding the results.

어떻게 이런 일이 생겼는지 믿을 수 없어요.

I can't believe how something like this happened.

As an Adjective (Modifier): To describe a person or thing directly, you change 없다 to 없는. This creates the modifier form. For example, '믿을 수 없는 이야기' (An unbelievable story). This is used to characterize the noun following it.

It is also important to note the difference between 안 믿다 and 믿을 수 없다. The former implies a choice ('I don't believe it' because I choose not to), whereas the latter implies an impossibility ('I can't believe it' because it is too shocking or the evidence is too weak). Using '믿을 수 없다' often carries a stronger emotional weight or a more objective statement about the lack of reliability.

그는 정말 믿을 수 없는 행동을 했어요.

He did something truly unbelievable.

In formal writing, such as news articles or academic papers, you might see the form 믿기 어렵다 (it is difficult to believe) used as a softer, more objective alternative. However, '믿을 수 없다' remains the most common and versatile way to express this concept across all levels of formality, provided the appropriate ending is attached.

You will encounter 믿을 수 없다 in a variety of settings, from the high-stakes drama of television to the mundane conversations of daily life. In the world of Korean entertainment, specifically K-dramas, this phrase is a staple. It is the go-to line when a character discovers a secret birth, a corporate betrayal, or a sudden miracle. The emotional delivery often emphasizes the '없다' part to show the depth of the character's shock.

In News and Media: When a shocking event occurs, such as a natural disaster or an unexpected political shift, news anchors might use this phrase to reflect the public's sentiment. Headlines often read '믿을 수 없는 참사' (An unbelievable disaster) to highlight the gravity and unexpected nature of the event.

뉴스를 보고도 믿을 수 없었어요.

Even after seeing the news, I couldn't believe it.

In everyday social life, you'll hear it used more casually. If a friend tells you they won the lottery or that they are moving to another country tomorrow, the natural response is '진짜? 믿을 수 없어!' This usage is very similar to the English 'No way!' or 'You're kidding!' It serves as a conversational reactive that validates the importance of the news being shared.

In business settings, the phrase might appear during discussions about data or projections that seem too good to be true. A manager might say, '이 수치는 믿을 수 없을 정도로 높네요' (These figures are unbelievably high). Here, it isn't necessarily negative; it can be used to describe something that exceeds expectations so much that it seems impossible. This versatility makes it one of the most useful descriptive phrases in the Korean language.

그 회사의 서비스는 정말 믿을 수 없을 만큼 훌륭해요.

That company's service is so great it's unbelievable.

One of the most frequent errors learners make with 믿을 수 없다 is confusing it with other negative forms of 'to believe.' Because Korean has multiple ways to express negation, choosing the wrong one can change the meaning of your sentence entirely.

Mistake 1: 믿을 수 없다 vs. 안 믿다: Learners often say '안 믿어요' (I don't believe) when they mean '믿을 수 없어요' (I can't believe). '안 믿어요' sounds like you are making a conscious decision to reject a fact or a person's words. '믿을 수 없어요' expresses that the thing is so shocking or the person so unreliable that belief is impossible.

❌ 저는 그 소식을 안 믿어요. (I don't believe that news - sounds like a choice).
✅ 저는 그 소식을 믿을 수 없어요. (I can't believe that news - expresses shock).

Mistake 2: Incorrect Modifying Form: When describing a noun, learners sometimes forget to change '없다' to '없는'. Saying '믿을 수 없다 사람' is grammatically incorrect. It must be '믿을 수 없는 사람' (An untrustworthy person).

Another mistake involves the scale of disbelief. Sometimes learners use '믿을 수 없다' for very minor things where '의심스럽다' (suspicious) or '이상하다' (strange) would be more appropriate. '믿을 수 없다' is a strong phrase. Using it for something like a slightly late bus might sound overly dramatic to native speakers. It's best reserved for significant events or serious character flaws.

❌ 버스가 늦는 것은 믿을 수 없어요. (Unbelievable that the bus is late - too dramatic).
✅ 버스가 늦는 게 이상해요. (It's strange that the bus is late).

Depending on the context, you might want to use a word that is more specific than 믿을 수 없다. Korean has a rich vocabulary for expressing doubt, shock, and unreliability. Understanding these alternatives will make your Korean sound more natural and nuanced.

의심스럽다 (Uisimseureopda): This means 'suspicious.' Use this when you don't necessarily 'not believe' something, but you have doubts. While '믿을 수 없다' is a definitive statement, '의심스럽다' is more about the feeling of uncertainty.

불신하다 (Bulsinhada): This is a more formal verb meaning 'to distrust.' It is often used in political or social contexts. For example, '정부를 불신하다' (to distrust the government). It sounds more academic and serious than '믿을 수 없다.'

그의 말은 항상 의심스러워요.

His words are always suspicious (I have doubts).

대단하다 (Daedanhada): When '믿을 수 없다' is used in a positive sense (like 'unbelievably good'), '대단하다' (great/amazing) is a common alternative. It focuses on the greatness of the feat rather than the speaker's disbelief.

Finally, for those looking for slang or informal expressions, you might hear 말도 안 돼 (It doesn't even make sense/No way) or 실화냐? (Is this for real?). These are very common among younger generations to express the 'unbelievable' aspect of a situation in a casual, punchy way.

How Formal Is It?

Fun Fact

The '수' in '수 없다' originally referred to a 'way' or 'method' in a physical sense, but over time it evolved into a grammatical marker for possibility, similar to 'way' in the English phrase 'no way.'

Pronunciation Guide

UK mi.dɯl su ʌp.t͈a

US mi.dəl su ʌp.tɑ

Stress is relatively even, but the '없다' (eopda) part often carries more emotional weight in speech.

Rhymes With

볼 수 없다 (bol su eopda) 할 수 없다 (hal su eopda) 갈 수 없다 (gal su eopda) 알 수 없다 (al su eopda) 살 수 없다 (sal su eopda) 올 수 없다 (ol su eopda) 줄 수 없다 (jul su eopda) 먹을 수 없다 (meogeul su eopda)

Common Errors

Pronouncing '믿을' as 'mi-deul' with a hard English 'D'. It should be a soft Korean 'ㄷ'.
Forgetting the tense 'p' sound in '없다', making it sound like 'eob-da' instead of 'eop-t͈a'.
Merging '수' and '없다' too quickly without a slight pause for clarity.
Incorrectly nasalizing the 'ㄹ' sound.
Failing to tense the 'ㄷ' in '다' after the 'ㅂ' sound in '업'.

Difficulty Rating

Reading 2/5

The grammar is standard A2-level '-(으)ㄹ 수 없다', making it easy to recognize.

Writing 3/5

Requires correct conjugation of '없다' and understanding of the modifier form '없는'.

Speaking 2/5

The pronunciation is straightforward, and it is a very common reactive phrase.

Listening 2/5

Commonly heard in media and daily life, usually with clear emotional intonation.

What to Learn Next

Prerequisites

믿다 (to believe) 없다 (to not have/not exist) 수 (way/possibility) 사람 (person) 말 (word/speech)

Learn Next

신뢰하다 (to trust) 의심하다 (to doubt) 확실하다 (to be certain) 비현실적이다 (to be unrealistic) 거짓 (falsehood)

Advanced

개연성 (probability/plausibility) 신빙성 (credibility) 불합리하다 (to be irrational) 회의론 (skepticism) 진위 (authenticity)

Grammar to Know

-(으)ㄹ 수 있다/없다 (Can/Cannot)

한국어를 할 수 있어요. (I can speak Korean.)

-는/은/ㄴ (Adjective Modifier)

재미있는 영화 (A fun movie)

-(으)ㄹ 만큼 (To the extent of)

죽을 만큼 사랑해요. (I love you to death.)

-(으)ㄹ 정도로 (To the degree of)

배가 아플 정도로 웃었어요. (I laughed to the point of my stomach hurting.)

-게 되다 (To become/come to be)

그를 좋아하게 됐어요. (I've come to like him.)

Examples by Level

믿을 수 없어!

I can't believe it!

Casual exclamation form.

정말 믿을 수 없어요.

I really can't believe it.

Polite ending -요 added.

그 소식은 믿을 수 없어요.

That news is unbelievable.

Subject + Particle '은' + Phrase.

이 가격은 믿을 수 없어요.

This price is unbelievable.

Describing a noun (price).

와! 믿을 수 없는 속도예요.

Wow! It's an unbelievable speed.

Modifier form '없는' used before a noun.

그는 믿을 수 없어요.

He is untrustworthy.

Describing a person's character.

내 눈을 믿을 수 없어.

I can't believe my eyes.

Common idiom for shock.

이건 믿을 수 없는 일이야.

This is an unbelievable thing.

Informal '이야' ending.

그 사람은 믿을 수 없는 사람이에요.

That person is an untrustworthy person.

Using the modifier form to describe a person.

거짓말이라서 믿을 수 없어요.

I can't believe it because it's a lie.

Using -(아/어)서 to give a reason.

어제 본 영화는 믿을 수 없을 만큼 슬펐어요.

The movie I saw yesterday was unbelievably sad.

-을 만큼 (to the extent of) with the phrase.

그의 약속을 믿을 수 없어요.

I can't trust his promise.

Object '약속' with object marker '을'.

이 이야기는 믿을 수 없는 이야기예요.

This story is an unbelievable story.

Repetition for emphasis.

결과가 너무 좋아서 믿을 수 없어요.

The results are so good I can't believe it.

Positive context of disbelief.

그 친구는 이제 믿을 수 없게 됐어요.

I have come to not trust that friend anymore.

-게 되다 (to become/come to be).

믿을 수 없는 광경을 봤어요.

I saw an unbelievable sight.

Past tense verb '봤어요' with the phrase.

아무리 생각해도 믿을 수 없는 일이에요.

No matter how much I think about it, it's unbelievable.

아무리 -(어/아)도 (no matter how much).

그 회사의 제품은 품질을 믿을 수 없어요.

You can't trust the quality of that company's products.

Topic '회사' and specific object '품질'.

믿을 수 없는 소문이 학교에 퍼졌어요.

An unbelievable rumor spread through the school.

Passive verb '퍼지다' (to be spread).

그가 범인이라는 사실이 믿을 수 없어요.

The fact that he is the culprit is unbelievable.

-는 사실 (the fact that...).

전문가의 의견이라도 믿을 수 없을 때가 있어요.

Even if it's an expert's opinion, there are times you can't believe it.

-(이)라도 (even if) and -을 때 (when/times).

그녀의 태도가 갑자기 변해서 믿을 수 없었어요.

I couldn't believe it because her attitude changed suddenly.

Adverb '갑자기' (suddenly).

믿을 수 없는 힘으로 위기를 극복했어요.

He overcame the crisis with unbelievable strength.

Instrumental particle '으로' (with/by).

이 데이터는 출처가 불분명해서 믿을 수 없네요.

This data is unreliable because the source is unclear.

Exclamatory ending '-네요'.

정치인의 말을 그대로 믿을 수 없는 경우가 많다.

There are many cases where you cannot take a politician's words at face value.

Written style ending '-다'.

현대 사회에서는 믿을 수 없는 정보가 넘쳐난다.

In modern society, unreliable information is overflowing.

Verb '넘쳐나다' (to overflow).

그의 성공 뒤에는 믿을 수 없는 노력이 있었다.

Behind his success, there was unbelievable effort.

Noun '뒤' (behind) used metaphorically.

눈앞의 상황이 너무 비현실적이라 믿을 수 없었다.

The situation before my eyes was so unrealistic that I couldn't believe it.

Adjective '비현실적' (unrealistic).

믿을 수 없는 반전이 영화의 재미를 더했다.

An unbelievable plot twist added to the fun of the movie.

Noun '반전' (plot twist).

그는 믿을 수 없는 속도로 문제를 해결해 나갔다.

He went on solving problems at an unbelievable speed.

-어 나가다 (to keep on doing).

이런 믿을 수 없는 실수를 하다니 정말 실망이야.

I'm so disappointed that you made such an unbelievable mistake.

-다니 (expressing a reaction to a fact).

과학적으로는 믿을 수 없는 현상이 발생했다.

A phenomenon occurred that is scientifically unbelievable.

Adverb '과학적으로' (scientifically).

인간의 이기심은 때로 믿을 수 없는 결과를 초래한다.

Human selfishness sometimes brings about unbelievable results.

Formal verb '초래하다' (to cause/bring about).

그 증언은 일관성이 없어 믿을 수 없다고 판단되었다.

The testimony was judged to be unreliable due to a lack of consistency.

Passive '판단되다' (to be judged).

기적이라고밖에 할 수 없는 믿을 수 없는 생환이었다.

It was an unbelievable survival that could only be called a miracle.

-라고밖에 할 수 없는 (could only be called...).

역사학자들은 그 기록의 진위 여부를 믿을 수 없다고 본다.

Historians view the authenticity of the record as unbelievable/unreliable.

Noun '진위 여부' (authenticity/truth or falsehood).

그의 논리는 겉보기에는 완벽하지만 믿을 수 없는 구석이 있다.

His logic is perfect on the surface, but there's something unreliable about it.

Expression '구석이 있다' (to have a certain aspect/side).

믿을 수 없는 경제적 호황이 이어지자 거품 논란이 일었다.

As an unbelievable economic boom continued, a bubble controversy arose.

Noun '호황' (economic boom) and '논란' (controversy).

인간의 뇌는 믿을 수 없을 정도로 복잡한 구조를 가지고 있다.

The human brain has an unbelievably complex structure.

-을 정도로 (to the degree of).

그의 배신은 나에게 믿을 수 없는 충격을 안겨주었다.

His betrayal gave me an unbelievable shock.

Verb '안겨주다' (to give/inflict a feeling).

포스트트루스 시대에 정보의 신뢰성을 믿을 수 없다는 것은 숙명과도 같다.

In the post-truth era, the inability to trust the reliability of information is like destiny.

Complex noun phrase '정보의 신뢰성' (reliability of information).

그 작가는 믿을 수 없는 화자로 독자들을 혼란에 빠뜨린다.

The author throws readers into confusion with an unreliable narrator.

Literary term '믿을 수 없는 화자' (unreliable narrator).

권력의 속성상 그들의 공약은 본질적으로 믿을 수 없는 측면이 강하다.

By the nature of power, their pledges inherently have a strong unreliable aspect.

Expression '속성상' (by its nature).

우주의 광활함은 인간의 지성으로는 믿을 수 없는 신비로 가득 차 있다.

The vastness of the universe is full of mysteries unbelievable to human intellect.

Formal ending '-로 가득 차 있다'.

그 이론은 믿을 수 없는 가설에 근거하고 있어 학계의 외면을 받았다.

The theory was ignored by the academic community because it was based on an unbelievable hypothesis.

Verb '외면을 받다' (to be ignored/shunned).

믿을 수 없는 속도로 진행되는 기후 변화는 인류의 생존을 위협한다.

Climate change, progressing at an unbelievable speed, threatens human survival.

Modifier '진행되는' (progressing).

그의 침묵은 믿을 수 없는 진실을 감추고 있는 듯 보였다.

His silence seemed to be hiding an unbelievable truth.

-는 듯 보이다 (to seem as if).

믿을 수 없는 우연이 겹쳐 비극적인 결말을 낳고 말았다.

A series of unbelievable coincidences overlapped, resulting in a tragic ending.

-고 말다 (ended up happening).

Common Collocations

눈을 믿을 수 없다

귀를 믿을 수 없다

믿을 수 없는 사실

믿을 수 없는 가격

믿을 수 없는 사람

믿을 수 없는 속도

도저히 믿을 수 없다

믿을 수 없는 결과

전혀 믿을 수 없다

믿을 수 없는 행운

Common Phrases

믿을 수 없어!

— I can't believe it! A common exclamation of shock.

진짜? 믿을 수 없어!

믿을 수 없게도

— Unbelievably/Incredibly. Used as an adverbial phrase.

믿을 수 없게도 그는 살아남았다.

믿을 수 없는 만큼

— To an unbelievable degree.

그녀는 믿을 수 없는 만큼 예뻤다.

믿을 수 없는 일

— An unbelievable thing or event.

세상에는 믿을 수 없는 일이 많다.

믿을 수 없는 이야기

— An unbelievable story or tall tale.

그건 정말 믿을 수 없는 이야기야.

믿을 수 없는 표정

— An expression of disbelief.

그는 믿을 수 없는 표정으로 나를 보았다.

믿을 수 없는 기적

— An unbelievable miracle.

믿을 수 없는 기적이 일어났어요.

믿을 수 없는 실수

— An unbelievable or stupid mistake.

어떻게 그런 믿을 수 없는 실수를 하니?

믿을 수 없는 능력

— An unbelievable ability or talent.

그는 믿을 수 없는 능력을 가진 사람이다.

믿을 수 없는 힘

— Unbelievable power or strength.

믿을 수 없는 힘이 솟아났다.

Often Confused With

믿을 수 없다 vs 안 믿다

A choice not to believe vs. an inability to believe.

믿을 수 없다 vs 믿지 못하다

Similar to '믿을 수 없다' but often implies a personal lack of ability to trust rather than the object's unreliability.

믿을 수 없다 vs 믿기지 않다

Used for surreal feelings ('It doesn't feel real') rather than character judgment.

Idioms & Expressions

"눈을 믿을 수 없다"

— To be unable to believe one's eyes because something is so shocking.

그 광경을 보고 내 눈을 믿을 수 없었다.

Common

"귀를 믿을 수 없다"

— To be unable to believe what one is hearing.

그의 고백에 내 귀를 믿을 수 없었다.

Common

"믿는 도끼에 발등 찍힌다"

— To be betrayed by someone you trusted (Literally: To have your foot chopped by a trusted axe).

친한 친구에게 사기를 당하다니, 믿는 도끼에 발등 찍힌 격이다.

Proverb

"입을 다물 수 없다"

— To be speechless with shock (Related to being unable to believe something).

그의 실력에 입을 다물 수 없었다.

Common

"꿈인지 생시인지"

— Whether it's a dream or reality (Used when something is too unbelievable).

복권에 당첨되다니 꿈인지 생시인지 믿을 수 없다.

Common

"하늘이 무너지는 것 같다"

— Feeling like the sky is falling (Used for unbelievable bad news).

그 소식은 하늘이 무너지는 것처럼 믿을 수 없었다.

Common

"귀신이 곡할 노릇이다"

— Something so strange and unbelievable it's like ghosts are wailing.

물건이 감쪽같이 사라지다니 귀신이 곡할 노릇이다.

Idiom

"자다가도 벌떡 일어날 일"

— Something so unbelievable or shocking you'd jump up from sleep.

그건 정말 자다가도 벌떡 일어날 만큼 믿을 수 없는 일이야.

Colloquial

"마른하늘에 날벼락"

— A bolt from the blue (Unbelievable sudden bad luck).

그의 갑작스러운 사고는 마른하늘에 날벼락처럼 믿을 수 없었다.

Proverb

"세상에 이런 일이"

— How can such a thing happen in the world? (Common reaction to unbelievable news).

세상에 이런 일이! 정말 믿을 수 없네요.

Common

Easily Confused

믿을 수 없다 vs 의심스럽다

Both express a lack of full belief.

의심스럽다 means you have doubts or suspicions. 믿을 수 없다 is a final conclusion that it is impossible to believe.

그의 의도가 의심스러워요 (I'm suspicious) vs. 그의 말은 믿을 수 없어요 (I can't believe him).

믿을 수 없다 vs 수상하다

Both relate to things that don't seem right.

수상하다 specifically means 'shady' or 'fishy.' 믿을 수 없다 is broader, covering shock and unreliability.

저 사람이 수상해요 (That person is shady).

믿을 수 없다 vs 거짓이다

If something is unbelievable, it might be a lie.

거짓이다 is a statement of fact ('It is a lie'). 믿을 수 없다 is a statement of the speaker's reaction or the object's quality.

그의 말은 거짓이다 (His word is a lie).

믿을 수 없다 vs 놀랍다

Both express shock.

놀랍다 simply means 'surprising.' 믿을 수 없다 emphasizes the 'belief' aspect of the surprise.

놀라운 소식 (Surprising news) vs. 믿을 수 없는 소식 (Unbelievable news).

믿을 수 없다 vs 신뢰할 수 없다

Direct synonyms.

신뢰할 수 없다 is more formal and specific to professional trust. 믿을 수 없다 is more emotional and general.

이 보고서는 신뢰할 수 없습니다 (Formal).

Sentence Patterns

[Noun]은/는 믿을 수 없어요.

그 소식은 믿을 수 없어요.

믿을 수 없는 [Noun]

믿을 수 없는 이야기

[Verb-는/은/ㄴ] 사실을 믿을 수 없다

그가 떠났다는 사실을 믿을 수 없다.

믿을 수 없을 만큼 [Adjective]

믿을 수 없을 만큼 커요.

도저히 믿을 수 없다

그의 핑계는 도저히 믿을 수 없다.

[Noun]을/를 믿을 수 없게 되다

친구를 믿을 수 없게 되었어요.

믿을 수 없는 [Noun]이/가 초래되다

믿을 수 없는 결과가 초래되었다.

[Noun]의 속성상 믿을 수 없는 측면

정치의 속성상 믿을 수 없는 측면이 있다.

Word Family

Nouns

믿음 (belief/trust)

불신 (distrust)

신뢰 (confidence/trust)

의심 (doubt)

신용 (credit/trust)

Verbs

믿다 (to believe)

믿어주다 (to give trust/believe someone)

신뢰하다 (to trust)

불신하다 (to distrust)

Adjectives

믿음직하다 (trustworthy)

미덥다 (reliable)

의심스럽다 (suspicious)

거짓말 (lie)

진실 (truth)

약속 (promise)

배신 (betrayal)

확신 (conviction)

How to Use It

frequency

Very High. It is used daily in both speech and writing.

Common Mistakes

Using '안 믿다' for shock. → 믿을 수 없다.
'안 믿다' sounds like a personal choice to ignore a fact, whereas '믿을 수 없다' expresses that the news is genuinely shocking.
Saying '믿을 수 없다 사람'. → 믿을 수 없는 사람.
You must use the modifier form '-는' when an adjective describes a noun in Korean.
Pronouncing it as 'Mi-deul su eob-da'. → Mi-deul su eop-t͈a.
The final syllable is tensed due to the preceding consonant. Pronouncing it softly sounds unnatural.
Using it for minor things like a late bus. → 이상하다 / 어색하다.
Using '믿을 수 없다' for trivial things makes you sound overly dramatic or like you are criticizing the bus driver's soul.
Confusing it with '할 수 없다'. → 믿을 수 없다.
'할 수 없다' means 'cannot do' or 'it can't be helped'. '믿을 수 없다' is specifically about belief.

Tips

Adjective Ending

Remember that when modifying a noun, '없다' always becomes '없는'. This is a rule for all '있다/없다' words in Korean. For example, '맛있는' (delicious) and '믿을 수 없는' (unbelievable).

Shock vs. Trust

Pay attention to context. If it's about a news event, it's 'shock.' If it's about a person's character, it's 'unreliability.' The two meanings are very distinct.

The Tense 'T'

The '다' in '없다' is pronounced as a tense 't' (t͈a) because of the 'ㅂ' (p) sound before it. This is a common phonological rule in Korean called 'tensing.'

Social Media

On Korean social media, you'll see this phrase used with exclamation marks to react to viral videos or shocking news stories.

Pairing with Adverbs

Use adverbs like '도저히' (simply/at all) or '전혀' (not at all) to strengthen the sense of disbelief. '도저히 믿을 수 없어요' sounds much stronger.

Intonation Matters

A sharp rise at the end usually signals shock, while a flat or falling intonation often signals disappointment or judgment.

Betrayal in Dramas

Watch K-dramas to hear this phrase in action. It's almost always used in the 'betrayal' scene or the 'big reveal' scene.

Modifier Placement

When using '믿을 수 없는', the noun it modifies must follow immediately. '믿을 수 없는 이야기' is correct; '이야기 믿을 수 없는' is not.

The 'Sue' Method

Remember 'su' (수) as 'Sue'. If you have to 'Sue' someone, it's because they are '믿을 수 없는' (untrustworthy).

Eyes and Ears

Memorize '눈을 믿을 수 없다' and '귀를 믿을 수 없다' as set idioms. They are used exactly like 'can't believe my eyes/ears' in English.

Memorize It

Mnemonic

Think of 'Me' (믿 - Mid) wanting to 'Dull' (들 - deul) the shock because I 'Sue' (수 - su) someone who is 'Up' (없 - eop) to no good. I can't believe it!

Visual Association

Imagine a person looking at a UFO in the sky. They rub their eyes and say '믿을 수 없어!' while pointing at the impossible sight.

Word Web

믿다 (Believe) 수 (Way/Ability) 없다 (None) 충격 (Shock) 의심 (Doubt) 거짓말 (Lie) 진실 (Truth) 신뢰 (Trust)

Challenge

Try to find three things today that are '믿을 수 없다'—one good, one bad, and one shocking—and describe them in Korean.

Word Origin

The phrase is a combination of the native Korean verb '믿다' (to believe) and the grammatical structure '-(으)ㄹ 수 없다' (cannot do). '믿다' has roots in Middle Korean and has remained stable in meaning for centuries.

Original meaning: To not have the way or possibility of believing.

Koreanic (Native Korean components).

Cultural Context

Be careful when using this phrase about a superior or elder in a professional setting, as it can sound accusatory and disrespectful.

English speakers often use 'unbelievable' as a positive compliment (e.g., 'That's unbelievable!'). In Korean, '믿을 수 없다' can also be positive, but it is slightly more common to use it for shock or negative unreliability.

The phrase is frequently shouted in the famous Korean variety show 'Running Man' when a betrayal occurs. It is the title or a key lyric in numerous K-pop songs dealing with heartbreak and betrayal. A famous news segment titled '세상에 이런 일이' (How can this happen?) often features '믿을 수 없는' stories.

Practice in Real Life

Real-World Contexts

Reacting to a surprise

정말 믿을 수 없어요!
우와, 믿을 수 없어!
이게 진짜예요? 믿을 수 없네요.
믿을 수 없는 일이 일어났어요.

Discussing an unreliable person

그 사람은 믿을 수 없어요.
믿을 수 없는 사람과는 일하지 마세요.
그의 말은 하나도 믿을 수 없어요.
믿을 수 없는 행동을 자주 해요.

Looking at a low price

믿을 수 없는 가격이네요.
이렇게 싸다니 믿을 수 없어요.
가격이 믿을 수 없을 만큼 저렴해요.
믿을 수 없는 세일이에요.

Hearing a rumor

그 소문은 믿을 수 없어요.
믿을 수 없는 이야기가 돌고 있어요.
출처를 믿을 수 없네요.
그건 믿을 수 없는 헛소문이에요.

Witnessing a great performance

믿을 수 없는 실력이에요.
그의 연기는 믿을 수 없을 정도였어요.
믿을 수 없는 무대를 봤어요.
저 선수의 속도는 믿을 수 없어요.

Conversation Starters

"최근에 믿을 수 없는 소식을 들은 적이 있나요? (Have you heard any unbelievable news lately?)"

"믿을 수 없는 사람을 만난 적이 있어요? (Have you ever met an untrustworthy person?)"

"자신의 눈을 믿을 수 없었던 순간은 언제였나요? (When was a moment you couldn't believe your eyes?)"

"믿을 수 없는 가격으로 물건을 산 적이 있나요? (Have you ever bought something at an unbelievable price?)"

"영화에서 믿을 수 없는 반전을 본 적이 있나요? (Have you seen an unbelievable twist in a movie?)"

Journal Prompts

오늘 겪은 일 중에서 가장 믿을 수 없었던 일에 대해 써 보세요. (Write about the most unbelievable thing that happened to you today.)

내가 만약 믿을 수 없는 능력을 가지게 된다면 무엇을 하고 싶나요? (If you had an unbelievable ability, what would you want to do?)

누군가를 믿을 수 없게 되었던 경험과 그 이유를 적어 보세요. (Write about an experience where you came to not trust someone and the reason why.)

세상에서 가장 믿을 수 없는 기적은 무엇이라고 생각하나요? (What do you think is the most unbelievable miracle in the world?)

정보가 넘치는 세상에서 믿을 수 있는 정보를 찾는 방법은 무엇일까요? (What is the way to find reliable information in a world overflowing with information?)

Frequently Asked Questions

10 questions

Yes! Just like in English, you can use it to describe something so good it's hard to believe. For example, '믿을 수 없는 행운' (Unbelievable luck) or '믿을 수 없는 실력' (Unbelievable skill).

'믿기지 않다' is often used when something feels like a dream or is surreal. '믿을 수 없다' is more about the logical impossibility of believing or a judgment of unreliability.

No, if you are reacting to their news, it's a very common and friendly way to show shock. However, if you say it about their personality, it is an insult.

You change '없다' to '없었다'. So, '믿을 수 없었어요' means 'I couldn't believe it' or 'He was untrustworthy.'

Yes, you can use it to say someone's faith is '믿을 수 없다' (unbelievable), though '신앙심' is the more specific word for religious faith.

'눈을 믿을 수 없다' (cannot believe one's eyes) is extremely common in both speech and literature.

People often use 'ㄹㅇ?' (Real?) or '실화?' (Is this real?) in texts, but '믿을 수 없어' is also typed out frequently.

Yes, '-(으)ㄹ 수 없다' is a grammar pattern that can be used with almost any verb to mean 'cannot do [verb].' For example, '갈 수 없다' (cannot go).

In formal reports, it is often changed to '신뢰도가 낮다' (reliability is low) or '신빙성이 부족하다' (lacks credibility).

It means 'impossible to believe.' It doesn't mean 'impossible to do' (that would be '할 수 없다').