Learn Hardcore Korean: geuneun geunyang jibe isseul geoya.

그냥 means “just/simply,” downplaying the action. It suggests he isn’t doing anything special or making a big deal about it—he’ll simply stay home. Without 그냥, it’s a plain statement; with 그냥, it can feel casual, offhand, or even a little dismissive.

Why is it 집에 and not 집에서?

With 있다 (to be/stay), the location takes -에 to mark where something/someone exists: 집에 있다. -에서 marks the place where an action happens (e.g., 집에서 공부하다). Saying 집에서 있다 is generally unnatural.

What exactly does 있을 거야 mean—future or a guess?

-ㄹ/을 거야 (from -ㄹ/을 것이다) can express:

Future: “He will stay at home.”
Conjecture/probability: “He’s probably at home” or “He’ll probably stay home.” Context (time words, situation) decides which reading is intended.

How formal/casual is 거야? What are polite alternatives?

거야 is casual/informal. Polite equivalents:

Standard polite: 있을 거예요.
Formal written/speech: 있을 것입니다. Match the subject term too (e.g., 그분은 for respect).

Can I drop 그는?

Yes. Korean often omits the subject when it’s clear from context. 그냥 집에 있을 거야 is very natural in conversation.

Is 그는 natural in everyday speech?

Not usually. 그/그는 feels written or a bit distant. In conversation, people use names or alternatives like 걔(는) (someone familiar/similar age), 그 사람(은) (that person), or 그분(은) (respectful).

What’s the difference between 그는 and 그가 here?

는 marks a topic (“as for him”), often implying contrast or shared knowledge.
가 marks the grammatical subject and can emphasize the doer (“HE [not someone else] will stay home”). Without a contrastive context, 그는 is more typical.

Can I move 그냥 to a different spot?

Yes. Common options:

그는 그냥 집에 있을 거야 (default, very natural)
그는 집에 그냥 있을 거야 (slight focus on the manner of staying)
그냥 그는 집에 있을 거야 (puts “just” more on the whole statement; less common) Keep 그냥 close to what you want to downplay.

Does this sentence ever mean “He is probably at home (now)”?

Yes. …있을 거야 can be used for present conjecture. Without a time phrase, it can mean either “He’s probably at home (now)” or “He’ll (just) be at home (later).” Add time words to clarify.

How would I say “He will only be at home,” not just “just be at home”?

Use 만 for exclusivity: 그는 집에만 있을 거야 (“He will be only at home”). 그냥 does not mean “only”; it means “just/simply.”

Why is there a space before 거야?

It comes from 있을 것 + 이야. 것 is a noun (“thing”) that the verb modifies, so there’s a space: 있을 것. In colloquial writing, 것 becomes 거, giving 있을 거야. (Full, more formal form: 있을 것이야.)

Any pronunciation tips?

집에 → [지베] (the ㅂ sounds like [b] between vowels)
있을 → [이쓸] (the ㅆ carries over as a strong [s] sound)
그냥 → [그냥]
거야 → [거야] Link the phrase smoothly: [그는 그냥 지베 이쓸 거야].

How do I make this respectful toward the subject?

Use the honorific verb 계시다 for 있다, and a respectful referent:

그분은 그냥 집에 계실 거예요.

How do I negate it?

Two common ways:

Not be at home: 그는 집에 안 있을 거야 / 그는 집에 있지 않을 거야.
Not “just” stay home (contrastive): 그는 그냥 집에 있지는 않을 거야.

Can I use 있을게 or 있겠어 instead?

있을게 is first-person (“I’ll stay [for you/then]”), not for third person.
있겠어/있겠지 expresses conjecture; 있겠지 can mean “I guess he’ll be at home,” which is fine but slightly different in nuance from 있을 거야.

How do I report what someone said?

Quoted speech (plain): 그는 그냥 집에 있을 거라고 했어. (“He said he’ll just stay home.”)
Colloquial hearsay: 그는 그냥 집에 있을 거래.

Is 그냥 ever rude?

By itself, no. It’s neutral and very common. But as a filler (“just, you know”), it can sound a bit noncommittal. More formal alternatives in some contexts: 그저 (literary), 단지 (only/merely, logical).