Learn Hardcore Korean: jigeum muneul dada.

지금 literally means “now.” In 지금 문을 닫아, it adds immediacy—“Close the door right now.” Without 지금, the command still works, but adding it emphasizes urgency or that you want the action done at once.

Why is 문 followed by 을?

을 is the object particle attached to nouns ending in a consonant (like 문). It marks “door” as the direct object of the verb. So 문을 닫아 = “(You) close the door.”

What form is 닫아, and what does it express?

닫아 is the plain (banmal), informal imperative of the verb 닫다 (“to close”). The stem 닫- takes the ending -아 because the vowel in the stem is ㅏ. Together, 닫 + 아 → 닫아, meaning “close!”

Why is the ending -아 used instead of -어요 or -습니다?

Korean has different speech levels for politeness.

-아 (banmal plain) is casual and used among close friends or to someone younger.
-아요 (haeyo style) is polite but not formal: 문을 닫아요.
-십시오/-습니다 (jondaetmal) is very formal: 문을 닫으십시오 or 문을 닫습니다.
So 닫아 is the most casual form.

How would you say “Please close the door” politely?

Here are two common polite versions:
• haeyo style: 지금 문을 닫아 주세요 (“Please close the door now.”)
• jondaetmal style: 지금 문을 닫아 주십시오 or 지금 문을 닫아 주세요 with higher respect.

Can you omit 지금 or the object marker 을?

• You can omit 지금 if context already implies “now.” Then you’d say 문을 닫아.
• Dropping 을 is possible in casual speech (문 닫아), but it’s less precise and feels rougher. In written or careful speech, keep the particle.

Are there any pronunciation changes in 문을 닫아?

Yes. When spoken naturally, you often hear assimilation:
• 문을 sounds like [무늘]
• 닫아 can drop the strong “t” so you get [다다] or slightly aspirated [다타], depending on speaker.
Together it may sound like [무늘다다] or [무늘타다], but in writing you still use 문을 닫아.

When is it appropriate to use this casual imperative?

Use the plain imperative -아/-어 only with:
• Close friends or family of the same or lower status/age
• People you’re very familiar with (e.g., younger siblings)
Never use it with strangers, superiors, or in formal settings.