Chissà dove abita.

In this sentence, chissà expresses uncertainty, speculation, or wondering.

A very literal way to think of it is:

• chi sa? = who knows?
• chissà = a fixed expression meaning something like who knows, I wonder, or heaven knows

So Chissà dove abita is the kind of thing someone says when they are wondering about a person’s home, without expecting an immediate answer.

Although it historically comes from chi sa (who knows), in modern Italian chissà is commonly treated as a single word when used as this expression.

The accent on à shows the stress:

• chi-ssà

That written accent is important in Italian because final stress is usually marked when needed.

Italian often omits subject pronouns when the verb ending already makes the person clear enough.

Here, abita is:

• third person singular of abitare = to live / to reside

So abita can mean:

• he lives
• she lives
• it lives
• sometimes you live in the formal Lei form, depending on context

Because Italian is a pro-drop language, saying only abita is completely normal.

It can mean either he lives or she lives.

Italian verbs usually do not show gender, so:

• abita = he/she lives

You understand which one is meant from context.

It could also refer to Lei (formal you) in the right context, though in a sentence like this learners will most often understand it as he/she lives.

Dove means where.

So the structure is:

• chissà = who knows / I wonder
• dove = where
• abita = he/she lives

Together: Who knows where he/she lives or I wonder where he/she lives.

Because this is an indirect question about place, and Italian uses the question word directly:

• Dove abita? = Where does he/she live?
• Chissà dove abita. = I wonder where he/she lives.

You use se for whether / if, not for where:

• Chissà se abita qui. = I wonder if he/she lives here.

And che would not work here because the idea is specifically where, so dove is the correct word.

After chissà in a sentence like this, Italian normally uses the indicative:

• Chissà dove abita.

That is the standard, natural choice.

Even though the sentence expresses uncertainty, this kind of indirect-question structure with dove commonly keeps the indicative. So for learners, the safest rule is:

• chissà + question word + indicative

Examples:

• Chissà quando arriva. = I wonder when he/she will arrive.
• Chissà perché dice così. = I wonder why he/she says that.

Yes. It is completely natural as a short, complete sentence.

Italian often uses short expressions like this in conversation. You do not need to add anything else.

It can stand alone just like English:

• Who knows where he lives.
• I wonder where she lives.

Yes, absolutely.

Both are possible, but there is a slight nuance:

• abitare = to reside, often a bit more specifically about one’s residence
• vivere = to live, broader and very common

In many everyday contexts, dove abita and dove vive are very close in meaning.
If you are talking about someone’s address or home, abitare often feels especially natural.

Yes, there is an important difference.

• Chissà dove abita = fixed expression meaning Who knows where he/she lives? / I wonder where he/she lives.
• Chi sa dove abita = literally the person who knows where he/she lives

So chissà as one expression is the one you want here.
If you split it into chi sa, the meaning changes.

It gives the sentence a tone of:

• curiosity
• uncertainty
• mild speculation
• sometimes a slightly dreamy or reflective feeling

It usually does not sound like a serious request for information. It sounds more like someone thinking aloud.

For example, if you see someone and wonder about their life, you might say:

• Chissà dove abita.
• Chissà con chi è.
• Chissà cosa pensa.

A simple pronunciation guide is:

• chissà ≈ kee-SA
• dove ≈ DO-veh
• abita ≈ A-bee-tah

Stress falls on:

• chis-SÀ
• DO-ve
• A-bi-ta

So the whole sentence sounds roughly like:

• kee-SA DO-veh A-bee-tah

It usually refers to the person’s current place of residence, but like English where he/she lives, it can also be understood more generally depending on context.

Most often, though, a learner should interpret it simply as:

• where he/she lives
• where he/she is living

The exact time reference comes from the situation, not from anything special in the sentence itself.