Learn Hardcore Portuguese (Portugal): O meu maior vício é olhar para o telemóvel antes de dormir. - My biggest addiction is looking at my phone before sleeping.

You can find Meu maior vício in speech or informal writing, but in Portugal it sounds either a bit emphatic, a bit Brazilian, or a bit informal/poetic. In Brazilian Portuguese, dropping the article (meu vício) is normal; in Portugal, keeping it (o meu vício) is the default and safest option.

What nuance does vício have here? Is it as strong as English addiction, or more like habit?

Literally, vício means vice or addiction (often something morally bad or unhealthy: drugs, gambling, smoking, etc.).

However, in everyday, informal Portuguese it’s also used hyperbolically for “bad habit” or “little obsession,” especially with things like phones, sweets, series:

O meu vício é chocolate. – I’m addicted to chocolate.
Ela tem o vício das redes sociais. – She’s hooked on social media.

So in your sentence it can be understood either as addiction or bad habit, depending on tone. It’s stronger and more colorful than neutral hábito and less cute than mania (little quirk).

Why is maior vício used instead of something like pior vício?

Maior literally means bigger or greatest, and by extension most important / main. So:

o meu maior vício ≈ my biggest / main vice
o meu pior vício ≈ my worst vice (morally, or in terms of consequences)

You could say O meu pior vício é olhar para o telemóvel..., but maior vício is more neutral and common: it just ranks it as the strongest or most significant one.

Why is olhar in the infinitive? Could I say a olhar para o telemóvel or olhando para o telemóvel instead?

Here olhar is acting like a noun phrase:

O meu maior vício é olhar para o telemóvel...
= My biggest vice is (the act of) looking at my phone…

In this kind of structure (X é [verb in infinitive]), Portuguese normally uses the bare infinitive:

O melhor é esperar. – The best thing is to wait.
O meu sonho é viajar. – My dream is to travel.

A olhar is mainly used with estar in European Portuguese for the present continuous:

Estou a olhar para o telemóvel. – I am looking at my phone.

Olhando is the gerund; in European Portuguese it sounds formal/literary and you would not put it here. So in your sentence, é olhar is the natural choice.

Why do we say olhar para o telemóvel instead of olhar o telemóvel?

In European Portuguese, olhar para is the usual way to say to look at:

Olho para o telemóvel. – I look at the phone.
Ela está a olhar para mim. – She is looking at me.

Olhar can sometimes take a direct object (olhar alguém/algo), but then it often has a nuance like examine / look over / check:

O médico olhou o doente. – The doctor examined the patient.
Posso olhar o teu trabalho? – Can I look over / check your work?

So for the everyday sense of “staring at your phone,” olhar para o telemóvel is the natural expression in Portugal.

In Brazilian Portuguese, olhar o celular (without para) is very common.

Could we use ver instead of olhar here?

Not very naturally. The basic difference is:

olhar – to look (at), intentionally directing your eyes
ver – to see, to perceive with your eyes (more passive)

You could say things like:

Gosto de ver vídeos no telemóvel. – I like watching videos on my phone.
Vou ver as mensagens no telemóvel. – I’ll check the messages on my phone.

But to describe the habit of just constantly staring at your phone, olhar para o telemóvel fits better than ver o telemóvel, which sounds odd by itself.

Why is it o telemóvel and not o meu telemóvel or meu telemóvel?

Both are possible; they just feel slightly different:

olhar para o telemóvel – look at the phone (understood as my phone from context; it’s the one by the bed)
olhar para o meu telemóvel – look at my phone (with explicit possession)

In everyday speech, when it’s obvious we’re talking about our own usual phone, Portuguese often just uses the definite article:

Vou desligar o telemóvel. – I’m going to turn off my phone.
Esqueci-me do telemóvel em casa. – I forgot my phone at home.

If you need to contrast owners, then you specify:

o meu telemóvel, o teu telemóvel, o telemóvel dele, etc.

What exactly does telemóvel mean? How is it different from telefone and from Brazilian celular?

In European Portuguese:

telemóvel = mobile phone / cell phone / smartphone (any portable phone)
telefone = phone in general; often understood as landline unless context suggests otherwise

So telemóvel in Portugal corresponds to Brazilian celular.

In Brazil:

celular – mobile phone
telefone – phone, landline or phone in general
telemóvel is not used.

Is antes de dormir always followed by an infinitive? Could I say antes de eu dormir?

Antes de is normally followed by an infinitive:

antes de dormir – before sleeping
antes de sair – before leaving
antes de comer – before eating

When the subject of that action is the same as the subject of the main clause, the simple infinitive is enough:

Vou tomar um chá antes de dormir. – I’ll have a tea before (I) sleep.

You can say antes de eu dormir to make the subject explicit or for emphasis. Grammatically this uses the personal infinitive, but for eu it looks the same as the normal infinitive:

eu dormir
tu dormires
ele / ela dormir
nós dormirmos
eles dormirem

So:

antes de eu dormir – before I sleep
antes de dormirmos – before we sleep

In everyday speech, antes de dormir is by far the most common in this sentence.

In English we say before going to sleep. Could we say antes de ir dormir or antes de ir para a cama in Portuguese?

Yes, both are fine and common, with small nuances:

antes de ir dormir – before going to sleep (very close to the English phrasing)
antes de ir para a cama – before going to bed (focuses on going to bed, not necessarily falling asleep immediately)
antes de me deitar – before lying down / going to bed

Your original antes de dormir is more generic and shorter, and it’s perfectly natural.

Is the word order fixed as O meu maior vício é olhar para o telemóvel antes de dormir? Could I start with Olhar para o telemóvel…?

You can definitely start with the verb phrase:

Olhar para o telemóvel antes de dormir é o meu maior vício.

This version:

sounds a bit more emphatic or explanatory (like a definition)
is still very natural and correct

Both orders are fine; the original one (O meu maior vício é…) is slightly more conversational and common.

How would I say my second biggest vice? Does maior change?

You can say:

O meu segundo maior vício é olhar para o telemóvel… – My second biggest vice is…

Here segundo is an ordinal (second) and maior is still a comparative (bigger). Both agree in gender and number with vício (masculine singular):

o meu segundo maior vício
a minha segunda maior preocupação – my second biggest concern

How do you pronounce vício and telemóvel in European Portuguese?

Approximate pronunciations (European Portuguese):

vício – ˈvi.siu
- stress on the ví
- í like ee in see
- final -cio sounds like siu (one syllable, a bit like see-oo joined)
telemóvel – tɛ.lɐ.ˈmɔ.vɛɫ
- stress on mó
- te ≈ te in ten but shorter
- le has a very reduced vowel (like a quick, weak uh)
- mó like mo in mop but a bit tenser
- final vel has a dark l; the e here is like eh

Spoken fast, it’s roughly: te-luh-MÓ-vel.

How would this sentence change in Brazilian Portuguese?

A very natural Brazilian version would be:

Meu maior vício é olhar o celular antes de dormir.

Main differences:

article with possessive often dropped: Meu maior vício (instead of O meu maior vício)
celular instead of telemóvel
olhar o celular is more usual than olhar para o celular in Brazil

Everything else (structure with é olhar, antes de dormir) works the same.

If I want to say I am addicted to looking at my phone before bed, can I still use vício?

Yes. Two natural options in European Portuguese:

Sou viciado em olhar para o telemóvel antes de dormir.
- viciado if you’re male, viciada if you’re female
Tenho o vício de olhar para o telemóvel antes de dormir. – I have the habit/addiction of looking at my phone before sleeping.

Both sound idiomatic; the first one focuses on you being addicted, the second on the habit itself.