Βασικά θέλω να μείνω σπίτι απόψε, γιατί είμαι κουρασμένος.

Here Βασικά works like basically, actually, or to be honest in natural speech.

It often does not mean something strictly logical like fundamentally. Instead, it can soften what you are about to say or introduce your real preference.

So in this sentence, it sounds a bit like:

• Basically, I want to stay home tonight...
• Actually, I want to stay home tonight...

In everyday Greek, βασικά is very common as a conversational marker.

Greek often leaves out subject pronouns when they are not needed.

That is because the verb ending already shows the person:

• θέλω = I want
• είμαι = I am

So adding εγώ would usually only be for emphasis or contrast:

• Εγώ θέλω να μείνω σπίτι απόψε = I want to stay home tonight

Without εγώ, the sentence sounds more neutral and natural.

After θέλω in Greek, you normally use να + verb.

So:

• θέλω να μείνω = I want to stay
• not θέλω μένω

This is a very important Greek pattern.
English uses to after want; Greek usually uses να.

Some more examples:

• Θέλω να φύγω = I want to leave
• Θέλω να κοιμηθώ = I want to sleep
• Θέλω να δω = I want to see

So να is required here.

This is about aspect, which is very important in Greek.

• να μείνω uses the aorist/subjunctive form
• να μένω would use the present/imperfective subjunctive

In this sentence, να μείνω is the natural choice because the speaker means a single whole action/event: staying home tonight.

So:

• θέλω να μείνω σπίτι απόψε = I want to stay home tonight

If you said θέλω να μένω σπίτι, that would sound more like:

• I want to stay at home regularly
• I want to be staying at home as a general habit/state

Also, μείνω is the aorist stem of μένω, so the stem changes:

• present: μένω
• aorist/subjunctive: μείνω
• future: θα μείνω

That stem change is normal and very common in Greek verbs.

In Greek, σπίτι can be used without an article in expressions where it means home, not just a/the house.

So:

• μένω σπίτι
• είμαι σπίτι
• πάω σπίτι

are very natural and idiomatic, similar to English stay home, be home, go home.

If you use the article and preposition:

• στο σπίτι

that is also correct, but it can sound a bit more literal: at home / at the house.

So in this sentence, μείνω σπίτι is a very natural way to say stay home.

Yes, absolutely.

Both are correct:

• να μείνω σπίτι
• να μείνω στο σπίτι

The difference is mostly nuance:

• σπίτι = more idiomatic, more like home
• στο σπίτι = a bit more explicit, more like in/at the house/home

In many contexts, native speakers use both.
In this sentence, σπίτι sounds very natural and conversational.

Απόψε means tonight.

It specifically refers to this evening / tonight, and it is very common in spoken Greek.

You could compare:

• σήμερα = today
• σήμερα το βράδυ = this evening / tonight
• απόψε = tonight

So απόψε is just a compact, natural way to say tonight.

Yes, γιατί can mean both:

• why?
• because

In this sentence, it means because, since it introduces the reason:

• γιατί είμαι κουρασμένος = because I’m tired

This is very common in Greek, just as some languages use the same word for both functions.

Compare:

• Γιατί φεύγεις; = Why are you leaving?
• Φεύγω γιατί είμαι κουρασμένος. = I’m leaving because I’m tired.

The meaning is clear from the structure and intonation.

Yes, you could say:

• Βασικά θέλω να μείνω σπίτι απόψε, επειδή είμαι κουρασμένος.

That is grammatical.

But γιατί is usually more common and natural in everyday speech for because.
Επειδή can sound a little more explicit, formal, or explanatory depending on context.

So in normal conversation, γιατί is probably the more natural choice here.

Κουρασμένος agrees with the speaker’s gender and number.

Here it is:

• masculine singular: κουρασμένος

If the speaker is female, it becomes:

• feminine singular: κουρασμένη

If you are talking about more than one person:

• masculine/mixed plural: κουρασμένοι
• feminine plural: κουρασμένες

So the sentence changes depending on who is speaking:

• ...γιατί είμαι κουρασμένη = if a woman is speaking

No, Greek word order is fairly flexible.

The given order is very natural:

• Βασικά θέλω να μείνω σπίτι απόψε, γιατί είμαι κουρασμένος.

But you can move some parts for emphasis:

• Βασικά απόψε θέλω να μείνω σπίτι...
• Θέλω βασικά να μείνω σπίτι απόψε...

Not every version sounds equally natural in every context, but Greek allows more movement than English.

A good rule for learners is:

• keep the original order unless you have a reason to emphasize something

The version you were given sounds smooth and idiomatic.

The comma separates the main statement from the reason clause:

• θέλω να μείνω σπίτι απόψε
• γιατί είμαι κουρασμένος

In writing, this helps show that the second part explains the first.

Greek punctuation with clauses like this is often similar to English punctuation, though usage can vary a bit by style. In this sentence, the comma is perfectly normal.

Yes, very natural.

It sounds like something a real speaker might say in conversation.
A few things make it especially natural:

• Βασικά as a conversational opener
• θέλω να μείνω with the correct verb pattern
• σπίτι without an article, meaning home
• απόψε for tonight
• γιατί είμαι κουρασμένος as a simple spoken reason

So this is a good sentence to learn from, because it combines several very common everyday patterns.