Não quero roubar nada.

Eu is optional here.

Portuguese often drops subject pronouns when the verb ending already makes the subject clear. In quero, the ending -o shows that the subject is I.

So both are correct:

• Não quero roubar nada.
• Eu não quero roubar nada.

The version without eu is very common and natural. You might include eu for emphasis, contrast, or clarity.

In Portuguese, não normally goes directly before the verb it negates.

So:

• Não quero = I do not want
• Não roubo = I do not steal

In this sentence, não is negating quero, so the structure is:

• não
  • quero
    • roubar nada

That is the normal word order.

Quero is the 1st person singular form of the verb querer.

• querer = to want
• quero = I want

So:

• Não quero = I don’t want

It is in the present tense.

After querer, Portuguese usually uses another verb in the infinitive.

So the pattern is:

• querer + infinitive
• quero roubar = I want to steal
• não quero roubar = I do not want to steal

This is very similar to English want to + verb.

Examples:

• Quero sair. = I want to leave.
• Não quero comer. = I don’t want to eat.

Yes. Nada means nothing.

So:

• roubar nada = steal nothing
• não quero roubar nada = literally I don’t want to steal nothing, but the real meaning is I don’t want to steal anything / I want to steal nothing

Portuguese commonly uses negative words together like this. That is normal and correct.

Yes, it is a kind of double negative, but in Portuguese that is standard grammar.

Portuguese often uses negative concord, which means multiple negative words work together in the same sentence.

Examples:

• Não vi nada. = I didn’t see anything.
• Não conheço ninguém. = I don’t know anyone.
• Nunca faço isso. = I never do that.

So não + nada is completely normal in Portuguese.

Normally, no. The natural form is:

• Não quero roubar nada.

Putting não before quero is the standard way to say I don’t want to steal anything.

Quero não roubar nada sounds unnatural in most situations. Portuguese usually negates the main verb directly:

• Não quero...
• not usually Quero não...

It can relate to both ideas, depending on context.

• roubar often means to steal
• it can also mean to rob, especially when someone is the victim

Examples:

• Roubar dinheiro = to steal money
• Roubar alguém = to rob someone

In Não quero roubar nada, the most natural translation is I don’t want to steal anything.

Normally, no. The most natural order is:

• Não quero roubar nada.

Portuguese does allow word order changes in special literary, poetic, or highly emphatic contexts, but for everyday speech you should stick to the standard order:

• não
  • quero
    • roubar
      • nada

So for a learner, this is the safe and natural version.

Não is one of the trickier Portuguese words for English speakers.

A rough guide:

• It sounds somewhat like nowng said through the nose, but that is only approximate.
• The vowel is nasal, which English does not really have in the same way.

Important points:

• It is one syllable
• the ão is nasal
• the final sound is not a strong English w

If you are learning Brazilian Portuguese, listening and repeating native audio is especially helpful for não and other -ão words like:

• pão
• mão
• irmão

Yes. It is simple, grammatical, and natural.

A Brazilian speaker would understand it immediately. It sounds like a straightforward statement of refusal or intention.

Depending on context, a speaker might also say things like:

• Eu não quero roubar nada.
• Não quero roubar nada, não. (more conversational in some contexts)

But the original sentence is perfectly normal:

• Não quero roubar nada.

Not in the same structure.

Compare:

• Não quero roubar nada. = I don’t want to steal anything / I want to steal nothing
• Quero roubar alguma coisa. = I want to steal something

If you use alguma coisa, the meaning changes unless you restructure the sentence.

You could say:

• Não quero roubar coisa alguma.

That is also correct and means basically the same as Não quero roubar nada, though nada is often the simpler, more common choice.

A useful breakdown is:

• Não = negation
• quero = I want
• roubar = to steal
• nada = nothing / anything

So the structure is:

• [negation] + [conjugated verb] + [infinitive] + [object]

More examples with the same pattern:

• Não quero comer nada. = I don’t want to eat anything.
• Não quero dizer nada. = I don’t want to say anything.
• Não quero comprar nada. = I don’t want to buy anything.