Prepositions with Adjectives | Portuguese (Brazil) Grammar

Just as verbs lexically select a preposition, so do many adjectives and nouns. This is regência nominal, nominal government. Cheio (full) demands de; apaixonado (in love) demands por; interessado (interested) demands em; parecido (similar) demands com. The logic is identical to verb government: the preposition is welded to the word and stored with it as a collocation. English does the same — full of, interested in, responsible for — but the Portuguese prepositions almost never line up with the English ones, which is exactly where learners stumble. The good news: many of these adjectives are the participle forms of verbs you already know, so they often borrow the verb's preposition.

Why nouns and adjectives govern prepositions

When an adjective describes a relationship to something else — full of what, interested in what, afraid of what — that relationship needs a preposition to attach the complement. The choice of preposition is fixed by the word, not by you.

O ônibus tava cheio de gente na hora do rush.

The bus was full of people during rush hour. (informal: tava = estava; de + a = da)

Ela é apaixonada por música dos anos 80.

She's in love with 80s music. (de + os = dos)

The mismatch is the whole challenge. English in love with uses with, but Portuguese uses por. English interested in matches interessado em by luck, but responsible for is responsável por, not the para an English speaker might guess.

Adjectives that take DE

The de group covers fullness, capacity, ease/difficulty, and pride. Note that fácil/difícil de take de before an infinitive (difícil de entender).

Adjective + de	Meaning
cheio de	full of
capaz de	capable of
fácil de	easy to
difícil de	difficult to
orgulhoso de	proud of
digno de	worthy of
livre de	free of/from
diferente de	different from

Esse sotaque é difícil de imitar.

That accent is hard to imitate.

Estou muito orgulhoso de você.

I'm very proud of you.

Note diferente de where English uses different from (or than) — a frequent slip.

Adjectives that take COM

The com group covers resemblance, satisfaction, compatibility, and marriage. Several of these mirror their verb (parecer-se com, casar com, satisfazer).

Adjective + com	Meaning
parecido com	similar to, like
satisfeito com	satisfied with
casado com	married to
compatível com	compatible with
preocupado com	worried about
generoso com	generous with/to
furioso com / bravo com	furious / angry with

Você é muito parecido com o seu pai.

You look a lot like your father.

Ela tá preocupada com a prova de amanhã.

She's worried about tomorrow's exam. (informal: tá = está)

Watch casado com (married to) and preocupado com (worried about) — both diverge from the English preposition.

Adjectives that take EM

The em group is small but high-frequency: skill or interest located in a domain.

Adjective + em	Meaning
interessado em	interested in
bom em / ruim em	good at / bad at
fraco em / forte em	weak at / strong at
experiente em	experienced in

Sempre fui bom em matemática, mas péssimo em história.

I was always good at math, but terrible at history.

Tô interessado naquele apartamento que você comentou.

I'm interested in that apartment you mentioned. (em + aquele = naquele)

Note bom em = good at (not good in), and the contraction em + aquele = naquele.

Adjectives that take A

The a group is the smallest. Acostumado notably allows both a and com in Brazil.

Adjective + a	Meaning
acostumado a / com	used to, accustomed to
fiel a	faithful to
favorável a	in favor of
contrário a	opposed to, contrary to
análogo a / semelhante a	analogous / similar to
anterior a / posterior a	prior to / subsequent to

Já estou acostumado a acordar cedo.

I'm already used to waking up early. (acostumado a + infinitive)

Não estou acostumado com esse barulho todo.

I'm not used to all this noise. (acostumado com + noun — equally acceptable in Brazil)

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Acostumado is the classic case where Brazilian usage accepts both a and com: acostumado a madrugar and acostumado com madrugar / com o barulho. Roughly, a tends to feel more natural before an infinitive and com before a noun, but neither is wrong. This kind of legitimate variation exists; don't agonize over it.

Adjectives that take POR

The por group is short but very common, and it's the one English speakers most often get wrong because English uses with, for, or of instead.

Adjective + por	Meaning
apaixonado por	in love with
responsável por	responsible for
ansioso por	eager for, anxious for
louco por	crazy about
conhecido por	known for

Sou completamente apaixonado por essa cidade.

I'm completely in love with this city.

Quem é responsável pela limpeza do prédio?

Who's responsible for cleaning the building? (por + a = pela)

Note responsável por (not para) and the contraction por + a = pela. Apaixonado por (in love with) is the single most common trap in this whole topic.

Nouns govern prepositions too

It is not only adjectives. Many nouns demand a fixed preposition before their complement — and again, the Portuguese choice rarely matches English.

Noun + prep	Meaning
medo de	fear of
vontade de	desire/urge to
saudade de	longing for, missing
interesse em / por	interest in
dúvida sobre / em	doubt about
amor a / por	love for
respeito por / a	respect for

Tenho um medo enorme de altura.

I have a huge fear of heights.

Bate uma saudade dos meus amigos de faculdade.

I get this longing for my college friends. (de + os = dos)

Que vontade de comer um açaí agora.

I really feel like eating an açaí right now. (vontade de + infinitive)

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The participle adjectives almost always inherit the preposition of their verb. Interessar-se POR/EM → interessado em; preocupar-se COM → preocupado com; apaixonar-se POR → apaixonado por. If you know the verb's government, you usually know the adjective's.

Common Mistakes

❌ Estou apaixonado com ela.

Incorrect — apaixonado takes por, not com.

✅ Estou apaixonado por ela.

I'm in love with her.

❌ Quem é responsável para isso?

Incorrect — responsável takes por, not para.

✅ Quem é responsável por isso?

Who's responsible for this?

❌ Tenho medo a aranhas.

Incorrect — medo takes de.

✅ Tenho medo de aranhas.

I'm afraid of spiders.

❌ Sou muito bom de cozinhar.

Incorrect — bom takes em for a skill, not de.

✅ Sou muito bom em cozinhar.

I'm very good at cooking.

❌ Ela é parecida a sua irmã.

Incorrect — parecido takes com, not a.

✅ Ela é parecida com a irmã.

She looks like her sister.

Key Takeaways

Adjectives and nouns lexically select prepositions, just like verbs: cheio de, apaixonado por, interessado em, parecido com, medo de.
The Portuguese preposition rarely matches English: responsável por (for), apaixonado por (with), bom em (at), casado com (to).
Participle adjectives usually keep their verb's preposition (preocupar-se com → preocupado com).
Some words allow legitimate variation: acostumado a and acostumado com are both fine in Brazil.
The complement contracts: cheio dos problemas, interessado naquilo, responsável pela área.

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