Learn Hardcore Portuguese (Portugal): Mesmo assim, ele sabe que é perigoso ficar arrogante e deixar de aprender. - Even so, he knows it is dangerous to become arrogant and stop learning.

“Mesmo assim” is a discourse connector, like “even so” / “still” / “nevertheless” in English. When it comes at the start of the sentence, it’s treated as an introductory phrase, so it’s normally followed by a comma:

Mesmo assim, ele sabe… = Even so, he knows…

You can move it, but the most natural positions are:

Ele, mesmo assim, sabe que… (less common, slightly heavier style)
Ele sabe, mesmo assim, que… (emphasises in spite of everything, he really does know…)

Putting it at the very end (Ele sabe que é perigoso ficar arrogante e deixar de aprender, mesmo assim.) is possible, but in neutral speech it sounds a bit marked or dramatic, as if you’re contrasting it strongly with another sentence that comes after or before it.

What nuance does “Mesmo assim” have compared to “ainda assim” or “no entanto”?

All three introduce contrast, but they’re not identical:

mesmo assim
Very common, quite neutral and conversational. Often translates as “even so” / “still”.
Suggests: given what we’ve just said, surprisingly / in spite of that…
ainda assim
Close in meaning to “mesmo assim”, but a bit more formal or written-sounding in European Portuguese. Often interchangeable with mesmo assim in this sentence.
no entanto
More like “however” / “nevertheless”. Feels more formal and typical of written language, essays, news, etc.

In your sentence, “Mesmo assim” sounds natural and conversational, which fits everyday European Portuguese very well.

Why is it “ele sabe que é perigoso…” and not “ele sabe que isso é perigoso…” or “ele sabe que é perigoso isso…”?

English needs a dummy subject “it”:
“He knows that it is dangerous to get arrogant…”

Portuguese does not need a dummy subject. It can just say:

Ele sabe que é perigoso ficar arrogante…

The subject of “é perigoso” is the whole idea that follows (ficar arrogante e deixar de aprender), so there is no isso.

The alternatives are possible but odd here:

Ele sabe que isso é perigoso…
This would point to some concrete “this” previously mentioned, not to the general idea of getting arrogant and stopping learning as an abstract behaviour.
Ele sabe que é perigoso isso…
Grammatically possible, but sounds clumsy and unnatural in this context.

So: to express “it is dangerous to…” + verb, Portuguese usually just says “é perigoso + infinitive”, with no extra pronoun.

Why is the verb after “que” in the indicative (“é perigoso”) and not in the subjunctive (“seja perigoso”)?

The choice of indicative vs. subjunctive depends mostly on the verb before que:

saber que
- fact → indicative
- Ele sabe que é perigoso… = He knows it is dangerous. (stated as a fact)
subjunctive is used with doubt, possibility, emotion, opinion, etc.:
- É possível que seja perigoso… = It’s possible that it may be dangerous…
- Duvido que seja perigoso. = I doubt that it’s dangerous.

So with “sabe que” in an affirmative sentence, you use the indicative (é perigoso).
You would use “seja perigoso” with verbs/expressions that don’t assert the fact.

What exactly does “ficar arrogante” mean? Is it “to be arrogant” or “to become arrogant”?

“Ficar” is a very flexible verb. Here it mainly means “to become / to get”:

ficar arrogante = to become arrogant / to get arrogant

Nuance:

ser arrogante – describes a more permanent characteristic:
- Ele é arrogante. = He is (a generally) arrogant person.
ficar arrogante – describes a change of state:
- Ele ficou arrogante depois do sucesso. = He became arrogant after the success.

In your sentence, “ficar arrogante” suggests that success or knowledge might make him arrogant, even if he wasn’t like that before.

Could I say “ser arrogante” or “tornar-se arrogante” instead of “ficar arrogante”? Are there differences?

All three verbs are possible, but with different flavours:

ficar arrogante
Very common, neutral, and idiomatic. Often implies changing into that state, but it can also feel a bit less strong than tornar-se.
tornar-se arrogante
More formal / bookish. Clearly expresses transformation:
- Ele tornou-se arrogante. = He turned into an arrogant person.
ser arrogante
Describes a trait, not the change:
- …é perigoso ser arrogante… = it’s dangerous to be arrogant (as a general quality).

In your original sentence, “ficar arrogante” is the most natural because the idea is “to end up getting arrogant and stop learning.”
“tornar-se arrogante” would also work, just a bit more formal; “ser arrogante” changes the nuance by focusing on the state, not on becoming.

How does “deixar de aprender” work grammatically? Does “deixar” always mean “to leave”?

“Deixar” has several meanings in Portuguese. The important patterns here are:

deixar + object = to leave (behind)
- Deixei o livro em casa. = I left the book at home.
deixar + person + infinitive = to let / allow
- Ela deixou o filho sair. = She let her son go out.
deixar de + infinitive = to stop / to no longer do something
- Deixar de fumar. = To stop smoking.
- Deixar de aprender. = To stop learning / to quit learning.

In your sentence, we have pattern 3: “deixar de aprender” = to stop learning.
So “deixar” does not always mean “to leave”; the preposition “de” completely changes the meaning.

Could I say “parar de aprender” instead of “deixar de aprender”? Is there any nuance?

Yes, you could say:

…é perigoso ficar arrogante e parar de aprender.

Both “parar de aprender” and “deixar de aprender” can mean “to stop learning”.

Nuances (often subtle and context‑dependent):

parar de + infinitive
Very direct: to stop doing something (usually at some point in time).
- Pare de falar. = Stop talking.
deixar de + infinitive
Often suggests giving something up / no longer doing it as a habit. It can feel a bit more permanent or about abandoning a practice.

In your sentence, both are acceptable in European Portuguese.
“Deixar de aprender” nicely suggests abandoning the attitude of continuous learning, not just pausing it.

Why don’t we repeat “ele” before “deixar de aprender”?

In Portuguese, when you have two infinitives joined by “e”, and they share the same subject, you usually mention the subject just once:

…é perigoso [ficar arrogante] e [deixar de aprender].

The understood subject for both infinitives is ele:

(Ele) ficar arrogante
(Ele) deixar de aprender

Repeating “ele” ( “ficar arrogante e ele deixar de aprender” ) would be unusual and only used for special emphasis or contrast. In normal speech, you drop it because it’s clear from context.

Is the word order “ele sabe que é perigoso ficar arrogante e deixar de aprender” fixed, or could I say “ele sabe que ficar arrogante e deixar de aprender é perigoso”?

Both word orders are grammatically correct:

Ele sabe que é perigoso ficar arrogante e deixar de aprender.
- Structure: é perigoso + infinitives.
- Very natural and common way to say “it is dangerous to…”.
Ele sabe que ficar arrogante e deixar de aprender é perigoso.
- The infinitive phrase “ficar arrogante e deixar de aprender” comes first and acts as the subject of “é perigoso”.
- Slightly more formal / heavier rhythm, but still correct.

In everyday European Portuguese, option 1 is more frequent and sounds smoother. Option 2 is more likely in writing or when you want to highlight the actions themselves as a single concept.

Why is it “perigoso” (masculine) and not “perigosa”? What is it agreeing with?

“Perigoso” here agrees with an implicit, abstract subject, which is treated as masculine singular by default in Portuguese:

É perigoso fumar. = It is dangerous to smoke.
É difícil aprender português. = It is hard to learn Portuguese.

When an adjective refers to:

a specific feminine noun, it changes:
- Esta situação é perigosa. (= This situation is dangerous.)
an abstract idea / clause (fumar, ficar arrogante e deixar de aprender) without an explicit noun, Portuguese normally uses masculine singular as the default:

So in your sentence:

Implicit subject: ficar arrogante e deixar de aprender (an abstract “thing”)
Adjective: perigoso (masculine singular by default)

That’s why it’s “é perigoso”, not “é perigosa”.

How is this sentence pronounced in European Portuguese, especially the reduced parts?

A careful European Portuguese pronunciation (one possible version) is:

Mesmo assim, ele sabe que é perigoso ficar arrogante e deixar de aprender.
/ˈmeʒ.mu ɐˈsĩ, ˈe.lɨ ˈsa.bɨ kɨ ɛ pɨ.ˈɾi.ɣo.zu fi.ˈkaɾ ɐ.ʁu.ˈɡɐ̃.tɨ i dɐj.ˈʃaɾ dɨ ɐ.ˈpɾẽ.dɨɾ/

Some features to notice:

mesmo → /ˈmeʒ.mu/ (the s sounds like the “s” in “measure”)
assim → /ɐˈsĩ/ (final -im is a nasal sound)
ele → /ˈe.lɨ/ (final -e is a reduced vowel /ɨ/)
que → /kɨ/ and often links tightly:
- sabe que → /ˈsa.bɨ.kɨ/ (almost like “sab’kı”)
perigoso → /pɨ.ˈɾi.ɣo.zu/ (first e is reduced /pɨ-/)
arrogante → /ɐ.ʁu.ˈɡɐ̃.tɨ/ (final -e is reduced /ɨ/ or very weak)
deixar → /dɐj.ˈʃaɾ/ (often sounds like “day-SHAR”)
de before consonant → usually reduced /dɨ/ or /dɐ/: de aprender → /dɨ ɐ.ˈpɾẽ.dɨɾ/

In normal speech, many vowels are very short and reduced, and words connect strongly, so the whole sentence flows as one long unit rather than separate words.