몰라요
I Don’t Know
On the surface, 몰라요 (mollayo) is as simple as it gets — “I don’t know.” But once you start using Korean in real life, you’ll quickly discover that this little word does a LOT more work than its English translation suggests.
In English, “I don’t know” can sometimes sound a bit blunt or dismissive. In Korean, 몰라요 is perfectly neutral and even polite. It signals honesty and humility — qualities that are genuinely valued in Korean social interaction. Saying 몰라요 means you’re being upfront rather than guessing or misleading someone.
Beyond literal ignorance, 몰라요 is also used to express uncertainty, confusion, or even mild frustration — kind of like “Who knows?” or “I have no idea!” depending on tone. It can pop up when you’re uncertain about your own feelings, when something is unpredictable, or when you just don’t want to commit to an answer. Context and intonation are everything with this word.
It also appears frequently in casual speech as a standalone emotional exclamation — imagine throwing your hands up and saying “I don’t know anymore!” — that frustrated yet relatable feeling is captured perfectly by a drawn-out 몰라~요 or just plain 몰라!
몰라요 comes from the verb 모르다 (moreuda), meaning “to not know.” Here’s how it’s built:
base verb “to not know”
verb stem
polite ending
I don’t know (polite)
⚠️ Important irregular rule: 모르다 is an 르 irregular verb. When you attach a vowel-based ending like 아요, the ㄹ in 르 doubles — the ㄹ drops into the syllable before it AND a new ㄹ appears. So 모르 + 아요 doesn’t become 모르아요 — it becomes 몰라요. This doubling of ㄹ is why the word sounds like “mol-la” not “mo-reu-a.”
The ending -아요 / -어요 is your standard polite present-tense ending in Korean (해요체, haeyoche). It’s the go-to level of speech when talking to strangers, coworkers, elders you’re not super close with, or in any situation where you want to sound respectful but still friendly.
The most basic use — when someone asks you something and you simply don’t have the answer.
When you’re not sure about something, even your own plans or feelings — like “Who knows?” or “I’m not sure.”
Said with exasperation — like “I give up!” or “I have no idea anymore!” Very common in casual speech.
Used playfully between friends as a soft refusal or dodging — kind of like “Not telling!” or “Figure it out yourself!”
When you don’t know a person, place, or thing — “I’m not familiar with it.”
몰라요 is everywhere in K-dramas and K-pop lyrics — especially in emotional scenes about confusing feelings: “I don’t know what to do…”
모르다 is a 르 irregular verb. The 으 drops and the ㄹ doubles before the 아요 ending. Never write or say 모르아요.
알아요 (arayo) means “I know” — the OPPOSITE of 몰라요. These get mixed up constantly. Remember: 알다 = to know, 모르다 = to not know.
몰라요 is polite but informal-leaning. In presentations, business meetings, or speaking to very senior people, use the formal 모릅니다 instead.
Here are all the key forms of 모르다 (moreuda) — to not know — that you’ll encounter:
| Form | Korean | Romanization | English |
|---|---|---|---|
| Dictionary / Base | 모르다 | moreuda | to not know |
| Casual (informal) | 몰라 | molla | I don’t know (casual) |
| Polite (standard) | 몰라요 | mollayo | I don’t know (polite) |
| Formal | 모릅니다 | moreumnida | I don’t know (formal) |
| Past tense (polite) | 몰랐어요 | mollasseoyo | I didn’t know |
| Past tense (formal) | 몰랐습니다 | mollasseumnida | I didn’t know (formal) |
| Negative question (polite) | 모르세요? | moreuseyo? | Don’t you know? / Do you not know? |
| If/when clause | 모르면 | moreumyeon | If (you) don’t know |
| Might not know | 모를 수도 있어요 | moreul sudo isseoyo | Might not know / Could not know |
| Don’t know yet | 아직 몰라요 | ajik mollayo | I don’t know yet |
🧠 몰라요 — Everything You Need to Remember
- 몰라요 (mollayo) = “I don’t know” in polite everyday Korean — safe to use with most people in most situations.
- It comes from the verb 모르다 (moreuda), which is a 르 irregular — the ㄹ doubles when adding vowel endings, giving us 몰라요 (NOT 모르아요).
- Drop the 요 → 몰라 (molla) for casual/informal speech with friends; add 습니다 → 모릅니다 (moreumnida) for formal situations.
- Don’t confuse it with 알아요 (arayo) = “I know” — the two are exact opposites and commonly mixed up by learners!
- 몰라요 can express genuine ignorance, uncertainty, frustration, playful refusal, and emotional confusion — tone and context make all the difference.