रविवार को मैं खाली हूँ।

In this sentence, को marks a specific time point: on Sunday.

So:

• रविवार = Sunday
• रविवार को = on Sunday

Hindi often uses को with days, dates, and other definite time expressions.

Examples:

• सोमवार को = on Monday
• शाम को = in the evening
• 1 जून को = on June 1st

In everyday speech, people sometimes drop को, especially when the meaning is obvious, but रविवार को is a very normal and clear form.

Yes. Both are correct.

Hindi word order is flexible compared with English, as long as the sentence remains clear.

These are both natural:

• रविवार को मैं खाली हूँ।
• मैं रविवार को खाली हूँ।

The first version puts a little more focus on Sunday.
The second begins with I and may feel more neutral to some learners because it resembles English order more closely.

Yes, खाली literally means empty, but it is also commonly used to mean free, available, or not busy, depending on context.

So in this sentence, मैं खाली हूँ means:

• I am free
• I am not busy
• I am available

Examples:

• कमरा खाली है। = The room is empty.
• मैं अभी खाली हूँ। = I am free right now.

So the exact English translation depends on context.

हूँ is the first-person singular present form of to be.

Since the subject is मैं = I, the correct form is हूँ.

Compare:

• मैं ... हूँ = I am
• तुम ... हो = you are
• वह ... है = he/she/it is
• हम ... हैं = we are

So:

• मैं खाली हूँ = I am free

You cannot use है here, because है goes with he/she/it or singular third-person subjects, not I.

Yes, a woman would also say मैं खाली हूँ.

खाली does not change here for masculine vs. feminine. It is an invariable adjective in this use.

So both are correct:

• A man: मैं खाली हूँ।
• A woman: मैं खाली हूँ।

This is different from adjectives like व्यस्त and many others? Actually व्यस्त is also invariable. A better contrast is with variable adjectives such as:

• अच्छा लड़का = good boy
• अच्छी लड़की = good girl

But खाली stays the same.

Sometimes yes, but it depends on style and context.

You may hear:

• रविवार मैं खाली हूँ
  or simply
• रविवार खाली हूँ

But रविवार को मैं खाली हूँ is clearer and more standard, especially for learners.

As a beginner, it is safest to use को with days of the week when you mean on that day.

No. रविवार is the standard formal/common word for Sunday, but इतवार is also widely used in everyday speech in many regions.

So both can mean Sunday:

• रविवार
• इतवार

Examples:

• रविवार को मैं खाली हूँ।
• इतवार को मैं खाली हूँ।

Both are understandable, though which one sounds more natural can depend on region and speaker.

There actually is a word for am: हूँ.

Hindi often puts the descriptive word before the form of to be:

• मैं खाली हूँ
  • मैं = I
  • खाली = free
  • हूँ = am

So Hindi structure here is very close to:

• I free am

That is normal Hindi word order.

By itself, रविवार को मैं खाली हूँ usually means I’m free on Sunday, in a general sense.

It does not specify exactly whether:

• you are free the whole day, or
• only at some time during that day

Context decides that.

If you want to be more specific, Hindi can say:

• रविवार को मैं पूरे दिन खाली हूँ। = I’m free all day on Sunday.
• रविवार को शाम में मैं खाली हूँ। = I’m free on Sunday evening.

Yes. Depending on what kind of free you mean, there are other possibilities.

Common alternatives:

• फ़्री = free (borrowed from English; very common in speech)
• उपलब्ध = available (more formal)
• फुर्सत में = at leisure / having free time

Examples:

• रविवार को मैं फ़्री हूँ। = I’m free on Sunday.
• रविवार को मैं उपलब्ध हूँ। = I’m available on Sunday.
• रविवार को मुझे फुर्सत है। = I have free time on Sunday.

But खाली हूँ is perfectly natural and common.

It is neutral and completely normal.

Nothing in रविवार को मैं खाली हूँ is especially formal or especially slangy. It works in everyday conversation.

If you want to sound a bit more conversational, many speakers might say:

• रविवार को मैं फ़्री हूँ।

If you want to sound more formal or professional:

• रविवार को मैं उपलब्ध हूँ।

But the original sentence is natural and correct.

You would change the subject and the form of to be:

• रविवार को हम खाली हैं। = We are free on Sunday.

Compare:

• मैं ... हूँ = I am
• हम ... हैं = we are

The adjective खाली stays the same; only the subject and verb change.

A simple learner-friendly pronunciation guide is:

ra-vi-vaar ko main khaa-lee hoon

A few notes:

• र is a light rolled or tapped r
• व sounds somewhere between English v and w
• मैं sounds like main but nasalized
• खा has a long aa
• हूँ is nasalized too

A rough natural rhythm: ra-vi-VAAR ko MAIN KHAA-lee hoon

The long vowels in रविवार, खाली, and हूँ are important for sounding more natural.