O resultado foi ruim.

Because resultado is a masculine noun in Portuguese, so it takes the masculine singular article o.

• o resultado = the result
• a resposta = the answer
• o problema = the problem

There is not always a logical reason for a noun’s gender, so this is something you usually learn together with the noun: o resultado, not just resultado.

Foi is the third-person singular preterite form of the verb ser.

Here, it means was in the sense of a completed past event:

• eu fui = I was / I went
• você/ele/ela foi = you/he/she was
• o resultado foi ruim = the result was bad

So the sentence is talking about the result as something in the past.

This is a very common question, because both can translate as was.

• foi = preterite, often used for a completed event or a specific outcome
• era = imperfect, often used for background description, habits, or something ongoing in the past

With o resultado foi ruim, the speaker is talking about the final outcome of something, so foi sounds natural.

Compare:

• O resultado foi ruim. = The result turned out bad. / The result was bad.
• O resultado era ruim. = The result was bad, in a descriptive or background sense.

In many situations, foi ruim is the more natural choice when talking about the end result of an event, test, game, decision, etc.

Yes, you might hear estava ruim in some contexts, but it gives a different nuance.

• foi ruim with ser often presents the result as a fact or overall judgment
• estava ruim with estar suggests a state or condition at that moment

Compare:

• O resultado foi ruim. = The result was bad.
  This sounds like a final evaluation.
• O resultado estava ruim. = The result was bad / looking bad.
  This can sound more temporary or situational.

For a final outcome, foi ruim is usually the best fit.

In the singular, ruim stays the same for both masculine and feminine nouns.

• o resultado ruim = the bad result
• a ideia ruim = the bad idea

In the plural, it becomes ruins:

• os resultados ruins
• as ideias ruins

So:

• singular: ruim
• plural: ruins

In Brazilian Portuguese, ruim is commonly pronounced roughly like hoo-EEN or roo-EEN, depending on accent and speaking style.

A few helpful points:

• the r at the beginning of a word in Brazilian Portuguese is often pronounced like an English h
• ruim usually has two syllables
• the stress is typically on the second syllable: ru-IM

You may also hear slight regional differences, but for most learners, thinking of it as hoo-EEN is a useful starting point.

Foi is usually pronounced approximately like foy in Brazilian Portuguese.

It is one syllable:

• foi → sounds similar to English foy

This word is very common, so it is worth practicing until it feels automatic.

Normally, in standard Portuguese, you would say O resultado foi ruim with the article.

Portuguese uses definite articles more often than English does. So where English may sometimes say Result was bad in notes or headlines, normal Portuguese usually prefers:

• O resultado foi ruim.

Without the article, Resultado foi ruim may sound incomplete or like a headline, note, or very informal speech.

Here, ruim is not directly modifying the noun inside the noun phrase. It is working as a predicate adjective after the linking verb foi.

Structure:

• O resultado = subject
• foi = linking verb
• ruim = predicate adjective

So the pattern is similar to English:

• The result was bad.

If you put the adjective directly with the noun, you get:

• o resultado ruim = the bad result

But that is a different structure from the sentence you were given.

For this sentence, ruim is the natural choice.

• ruim = bad, poor, unfavorable
• mau = bad, evil, morally bad, or the opposite of bom in some contexts

With resultado, Portuguese normally uses ruim:

• O resultado foi ruim. ✅
• O resultado foi mau. ⚠️ possible in limited contexts, but much less natural here

So if you are evaluating an outcome, score, performance, or consequence, ruim is usually the right word.

Yes. Ficou ruim is also very common, but it adds the idea of became or ended up bad.

Compare:

• O resultado foi ruim. = The result was bad.
• O resultado ficou ruim. = The result turned out bad / ended up bad.

Both are natural, but ficou ruim emphasizes the change or final development a bit more.

The plural version is:

Os resultados foram ruins.

Changes:

• o → os
• resultado → resultados
• foi → foram
• ruim → ruins

So:

• singular: O resultado foi ruim.
• plural: Os resultados foram ruins.