yaksogeul kkamppakhaesseoyo.

I forgot the appointment.

Breakdown of yaksogeul kkamppakhaesseoyo.

• ~을: object particle
• 약속: appointment
• 깜빡하다: to forget

Questions & Answers about yaksogeul kkamppakhaesseoyo.

What exactly does 약속 mean here—“promise” or “appointment”?

약속 can mean both “promise” and “appointment/plan to meet.” Context decides. In everyday speech, it often covers both. For a restaurant booking or a doctor’s slot specifically, Koreans also say 예약 (reservation), e.g., 치과 예약.

Why is it 을 after 약속 and not 를?

을/를 is the object marker. You use 을 after a noun ending in a consonant and 를 after a noun ending in a vowel. 약속 ends with ㄱ, so it’s 약속을.

Can I drop the object particle and just say 약속 깜빡했어요?

Yes. In casual or fast speech, object particles are often omitted: 약속 깜빡했어요. Keeping it (약속을) is never wrong and is more careful/clear.

Why is it in the past tense (했어요) instead of present (해요)?

Forgetting is a completed event, so Koreans naturally use the past: 깜빡했어요. Present (깜빡해요) would sound odd unless describing a habitual tendency (“I tend to forget”).

What nuance does 깜빡하다 have compared to 잊다, 잊어버리다, and 까먹다?

• 깜빡하다: a momentary lapse—“it slipped my mind.” Mild, apologetic.
• 잊다: neutral “to forget,” common in writing or careful speech (약속을 잊었어요).
• 잊어버리다: “forget completely/by accident,” adds a sense of finality or regret.
• 까먹다: very colloquial/slangy “to forget,” can feel blunt or rude in formal contexts.

Is 깜빡 a separate word or part of a verb?

깜빡 is an ideophone/adverb meaning “blink/for a moment.” With 하다 it forms the verb 깜빡하다 (“to forget momentarily; to blink”). In your sentence, 깜빡하다 is one verb: 깜빡했어요.

I’ve seen 깜빡 잊었어요. Is that different from 약속을 깜빡했어요?

Both are natural.

• 약속을 깜빡했어요 = “I (momentarily) forgot the appointment/promise.”
• 약속을 깜빡 잊었어요 = using 깜빡 as an adverb modifying 잊다. Spacing: 깜빡했어요 (no space, one verb) vs 깜빡 잊었어요 (space, adverb + verb).

Is 깜빡 the only correct spelling? What about 깜박?

깜빡 is the more common and recommended spelling. 깜박 also appears and is accepted for the adverb in many dictionaries, but the verb is conventionally written 깜빡하다. You’ll most often see 깜빡했어요 and 깜빡 잊었어요.

How do I pronounce 약속을 깜빡했어요?

• Romanization: yaksogeul kkamppakhaesseoyo.
• Rough sounds: “yak-so-geul kkam-ppak-hae-sseo-yo.”
• Natural connected speech: 약소글 깜빠캐써요 (liaison/aspiration make it sound like this).

Can I say 약속은 깜빡했어요?

Yes. Using the topic marker 은 shifts focus to “as for the appointment, I forgot (it).” It’s useful for contrast (e.g., 다른 건 기억했는데 약속은 깜빡했어요). With 을, you’re simply marking it as the object.

What’s the difference between 약속 and 예약?

• 약속: a plan/promise to meet someone (friends, colleagues). Also used colloquially for appointments.
• 예약: a reservation/booking (restaurant, hotel, tickets) and for medical appointments (진료 예약). Both can appear with professionals: 치과 약속/치과 예약—예약 is more precise.

How do I make this more formal or add honorifics?

• To be more formal: 약속을 깜빡했습니다.
• About a respected subject: 어머니께서 약속을 깜빡하셨어요. (add 시 for subject honorific)
• If speaking to a boss/client, pair it with an apology: 약속을 깜빡했습니다. 죄송합니다.

Is 까먹었어요 okay here?

Grammatically yes (약속을 까먹었어요), but it’s slangy/casual. Avoid with seniors, teachers, or in formal situations. Prefer 깜빡했어요, 잊었어요, or 잊어버렸어요.

Can I intensify it, like “I completely forgot”?

Yes:

• 완전/정말 깜빡했어요.
• 완전히 잊어버렸어요. Note: 깜빡 already implies a lapse; 완전 깜빡했어요 is common in speech even if a bit redundant.

Is “안 깜빡했어요” the natural way to say “I didn’t forget”?

It’s understandable but not the most natural. More idiomatic:

• 약속 잊지 않았어요. (“I didn’t forget the appointment.”)
• 약속 기억하고 있었어요. (“I was remembering it.”)

Can 깜빡하다 be used for blinking or lights flickering?

Yes. It also means “to blink/flicker.”

• 불이 깜빡해요/깜빡거려요. (“The light is flickering.”)
• 눈을 깜빡했어요. (“I blinked.”)

Do I need to say “I” (저/제가) in the sentence?

No. Korean often drops the subject when it’s clear from context. You can add it for clarity/emphasis:

• 제가 약속을 깜빡했어요. (puts emphasis on “I.”)

Is “약속을 깜빡 했어요” with a space acceptable?

No. When using the single verb 깜빡하다, write it together: 깜빡했어요. Use a space only when 깜빡 modifies a different verb: 깜빡 잊었어요.

Any natural ways to follow up with an apology or fix?

Common follow-ups:

• 정말 죄송해요/죄송합니다. 다시 일정 잡을 수 있을까요?
• 늦게 연락드려 죄송합니다. 약속을 깜빡했습니다.