Learn Hardcore Portuguese (Portugal): O meu pai está de mau humor hoje.

You can drop the article in some cases, but that’s less common in European Portuguese and more typical of Brazilian Portuguese or very formal/written styles.

Some common cases where the article is often dropped:

After the verb ser in short identifications:
- Ele é meu pai. – He is my father.
In direct address (calling someone):
- Ó pai! – Dad!
- Ó meu pai! – (more emotional/affectionate, but still no article before meu here)

In your sentence, the most natural version in European Portuguese is O meu pai está de mau humor hoje.

Could I say Meu pai está de mau humor hoje without the article? Is it wrong?

It’s not wrong, but in Portugal it sounds less natural in everyday speech.

O meu pai está de mau humor hoje. – Most natural in European Portuguese.
Meu pai está de mau humor hoje. – Sounds more Brazilian or a bit more written/formal in a European context.

In Brazil, dropping the article is very common: Meu pai chegou. is the default.
In Portugal, O meu pai chegou. is the default.

Why is it está and not é here?

Portuguese uses estar for temporary states/conditions and ser for more permanent, characteristic qualities.

estar = to be (temporary, changeable, or current state)
ser = to be (permanent traits, identity, time, origin, etc.)

Being in a bad mood is a temporary state (just today), so you use estar:

O meu pai está de mau humor hoje. – My father is (currently) in a bad mood today.

If you said:

O meu pai é de mau humor.
this would sound like “My father is by nature bad-tempered / grumpy” (a permanent trait), and even then, it’s not the most natural phrasing; you’d more likely say:
O meu pai é mal-humorado. – My father is bad-tempered (as a characteristic).

What is the difference between mau and mal, and why is it mau humor here?

Mau and mal are different words:

mau = bad (adjective)
- Modifies a noun: mau filme (bad film), mau dia (bad day), mau humor (bad mood).
mal = badly / poorly (adverb) or sometimes evil (noun/adjective in specific contexts)
- Modifies a verb or adjective:
  - Ele dormiu mal. – He slept badly.
  - Sinto-me mal. – I feel bad / ill.

In de mau humor:

humor is a masculine noun.
The adjective for “bad” must agree in gender with it: mau (masculine), not má (feminine).

So:

mau humor (correct)
mal humor (incorrect in standard Portuguese)

Why do we say de mau humor and not em mau humor or something else?

Estar de mau humor is a fixed expression in Portuguese. The normal structure is:

estar de bom humor – to be in a good mood
estar de mau humor – to be in a bad mood

The preposition de here roughly corresponds to English “in (a mood/temper)” and is idiomatic. You wouldn’t say:

✗ estar em mau humor – sounds wrong/unnatural.

There are other estar de + noun/adjective expressions that describe a current state:

estar de férias – to be on holiday
estar de folga – to be off (from work)
estar de pé – to be standing

So de fits into this pattern of “being in a certain state or situation.”

Does mau agree with pai or with humor in this sentence?

Mau agrees with humor, not with pai.

Structure:

O meu pai – subject
está – verb
de mau humor – prepositional phrase describing his state

Inside de mau humor:

humor is the noun (masculine singular)
mau is the adjective modifying humor, so it must be masculine singular too.

You would also say:

de bom humor – in a good mood
(not boa because humor is masculine)

Can I say O meu pai está mal-humorado hoje instead of está de mau humor?

Yes, that’s possible and correct, but there’s a nuance:

O meu pai está de mau humor hoje.
Very common, neutral, idiomatic, perhaps a bit more colloquial.
O meu pai está mal-humorado hoje.
Also correct; feels slightly more descriptive or formal/literary, and it presents mal-humorado clearly as an adjective meaning “bad-tempered / in a bad mood.”

In Portugal, another very common alternative is:

O meu pai está mal-disposto hoje.
This can mean “in a bad mood” but also sometimes “feeling physically unwell”, so context matters.

All three can be used, but estar de mau humor is extremely common and clear.

Why is it hoje on its own, without a preposition like “em hoje”?

Hoje is an adverb of time, like “today” in English. Adverbs don’t need prepositions:

Hoje está frio. – Today it’s cold.
Chego amanhã. – I arrive tomorrow.
Ontem choveu. – Yesterday it rained.

So hoje is used by itself:

O meu pai está de mau humor hoje.

You would not say:

✗ em hoje – incorrect
✗ no hoje – incorrect in this meaning

(There are special abstract uses like no hoje em dia = “in today’s world”, but that’s a different structure.)

Can I move hoje to the beginning of the sentence?

Yes. Word order with adverbs of time is quite flexible:

O meu pai está de mau humor hoje. – neutral.
Hoje o meu pai está de mau humor. – also natural and maybe gives a little extra focus to “today.”

Both are fine in European Portuguese. Starting with Hoje is very common in speech and writing.

How do I pronounce mau and mal? They look similar.

The pronunciation is very close, and in fast speech many people sound almost the same, but in careful European Portuguese:

mau – ends in a kind of open -ao sound, similar to “mow” in English but shorter and more nasalized depending on the accent.
mal – ends in a dark -al sound, like English “mull” but with a clearer a.

In practice:

mau humor is pronounced roughly: [maw u-MOR] (European Portuguese: final r often weak / almost gone).
mal in sinto-me mal is more like [mahl].

Context usually disambiguates, and native speakers rely more on grammar and meaning than on the tiny sound difference.

What is the difference between está and esta? They look almost the same.

está (with accent) = 3rd person singular of the verb estar (he/she/it is).
- Ele está cansado. – He is tired.
- O meu pai está de mau humor. – My father is in a bad mood.
esta (no accent) = demonstrative adjective/pronoun, meaning “this” (feminine).
- esta casa – this house
- Gosto desta. – I like this one (fem.).

So in your sentence it must be está with an accent, because it’s the verb “is.”

Can I drop meu and just say O pai está de mau humor hoje?

Yes, in family contexts this is quite common in European Portuguese.

Inside a family, people often refer to parents like this:

O pai chega às seis. – Dad arrives at six.
A mãe já saiu. – Mum has already gone out.

In that context, everyone knows which father/mother is meant, so you don’t need meu/minha.

So:

O pai está de mau humor hoje.
can be perfectly natural if said by a child or spouse, meaning “Dad is in a bad mood today.”

But if you’re speaking to someone outside the family and want to make it clear you’re talking about your father, O meu pai is safer and more explicit.

How would the sentence change if I talk about my mother instead of my father?

You have to change the words that refer to the person:

O meu pai está de mau humor hoje. – My father is in a bad mood today.
A minha mãe está de mau humor hoje. – My mother is in a bad mood today.

Changes:

O → A (masculine → feminine article)
meu → minha (masculine → feminine possessive)
pai → mãe (father → mother)

Mau humor stays the same, because humor is still masculine, regardless of who is in that mood.

How would I turn this into a question: “Is your father in a bad mood today?”

You mainly change meu to teu (informal “your”) and use question intonation or a question mark:

O teu pai está de mau humor hoje? – Is your father in a bad mood today?

If you want to start with Hoje:

Hoje o teu pai está de mau humor?

You don’t need to invert the verb as in English. Word order can remain the same; the question mark/intonation does the job.

How do I say this in the negative: “My father is not in a bad mood today”?

Add não before the verb:

O meu pai não está de mau humor hoje.
– My father is not in a bad mood today.

Basic pattern:

[subject] + não + [verb] + ...

Examples:

Eu não estou cansado. – I’m not tired.
Ela não está em casa. – She is not at home.

Could I say O meu pai é de mau humor hoje to mean the same thing?

No. That sounds incorrect or very strange.

é (from ser) normally describes permanent traits or identity.
está (from estar) describes current / temporary states.

“Being in a bad mood today” is clearly temporary, so only estar works:

O meu pai está de mau humor hoje. ✅

O meu pai é de mau humor would sound like “My father is (by nature) bad-mooded”, and even for that idea, native speakers would prefer:

O meu pai é mal-humorado. – My father is bad-tempered.

Is there a more colloquial or softer way to say someone is in a bad mood in European Portuguese?

Yes, some common alternatives in Portugal include:

O meu pai hoje não está muito bem-disposto.
– Literally “is not very well-disposed today”; can mean he’s not in a great mood.
O meu pai hoje está um bocado rabugento.
– “My father is a bit grumpy today.” (rabugento is “grumpy”.)
O meu pai hoje está um bocado chateado.
– “My father is a bit annoyed today.”

These can sound slightly softer or more informal than de mau humor, depending on tone and context.