Learn Hardcore Korean: jigeum changmuneul datgo sipeoyo.

지금 means “now,” indicating the time when you want to close the window.
It’s common at the front for emphasis, but you could also say 창문을 지금 닫고 싶어요 without changing the meaning.
Putting 지금 at the very end (e.g. 창문을 닫고 싶어요 지금) sounds awkward in Korean, so stick to the front or just before the verb.

Why is there an -을 on 창문? Can I drop it?

을 is the object marker for verbs. Here 창문을 marks 창문 (“window”) as the thing being closed.
Dropping 을 (창문 닫고 싶어요) sounds like a fragment or casual note. In polite sentences, you should include 을 to keep the grammar clear.

How is 닫고 싶어요 formed? What are its parts?

닫고 싶어요 breaks down into three parts:

닫- (stem of 닫다, “to close”)
-고 (connective ending that links actions or attaches 싶다)
싶어요 (polite form of 싶다, “to want”)
So 닫-고 싶-어요 literally means “(I) want to do the action ‘close.’”

What exactly does -고 싶다/싶어요 mean?

-고 싶다 attached to a verb stem expresses “to want to do [that verb].”
싶다 on its own is an adjective meaning “to be eager/hoping.” You don’t say 싶다 alone after a noun; it always follows a verb with -고.
Politeness is shown by changing 싶다 to 싶어요 (casual polite) or 싶습니다 (more formal).

Why can’t I use 원하다 instead of 닫고 싶다?

원하다 means “to want” or “to desire,” but it typically takes a noun object: 나는 평화를 원해요 (“I want peace”).
For wanting to perform an action (like “close”), Korean uses -고 싶다 rather than 원하다. Saying 창문을 닫기를 원해요 is grammatically possible but archaic/formal—learners almost always use 닫고 싶어요.

Can I use -고 싶다 for someone else’s desire?

No. -고 싶다 expresses your own desire. To talk about a third person (he, she, they), you need -고 싶어 하다:

Why is there no subject in 지금 창문을 닫고 싶어요?

Korean often drops subjects when they’re obvious from context.
Here it’s assumed to be I or we depending on the situation. If you needed clarity, you could say 저는 지금 창문을 닫고 싶어요.

How polite/formal is -고 싶어요? Could I say -고 싶습니다?

-고 싶어요 is polite but casual—suitable for conversations with strangers or colleagues.
-고 싶습니다 is more formal (used in presentations, announcements, or with elders where extra respect is needed). Both are correct; choose based on your relationship with the listener.

Can I say 닫고 싶어 instead of 닫고 싶어요?

닫고 싶어 is the informal, plain form—used with close friends or younger people.
닫고 싶어요 is the same tense and meaning but polite.
Never mix levels: use 싶어 with 반말 (informal) and 싶어요 with 존댓말 (polite).

Is there anything special about pronouncing 닫고?

In fast speech, the ㅌ in 닫- can sound closer to a [t̚] ending, and the following ㄱ in -고 becomes [k͈] due to tense consonant assimilation.
You’ll hear something like [닫̚꼬] (batchim ㅌ + initial ㄱ → tense ㄲ). This is normal and nothing to worry about.

Can I change the word order: what about 창문을 닫고 싶어요 지금 or 닫고 싶어요 창문을?

Korean is relatively flexible, but these two options are unnatural:
• 창문을 닫고 싶어요 지금 (time at the end sounds off)
• 닫고 싶어요 창문을 (verb phrase should come at the end in standard SOV order)
Stick to [Time] [Object] [Verb]: 지금 창문을 닫고 싶어요 or 창문을 지금 닫고 싶어요.