Foi azar, mas ninguém teve culpa pelo atraso.

Foi is the preterite form of ser, and here it presents the situation as a completed fact:

• Foi azar = It was just bad luck

Portuguese often uses the preterite this way when talking about a specific event that happened and is now finished.

If you said era azar, it would usually sound less natural here. Era often gives more of a background, description, or ongoing past idea, while foi fits a single concluded situation better.

So in this sentence, foi is the natural choice because the speaker is summing up what happened.

Here, azar means bad luck or misfortune.

So:

• Foi azar = It was bad luck
• More naturally in English: It was just bad luck

In Brazilian Portuguese, azar is a very common everyday word. Depending on context, it can also appear in expressions like:

• Que azar! = What bad luck!
• Foi puro azar. = It was pure bad luck.

Portuguese often leaves out the article with abstract nouns in short judgments like this.

So Foi azar sounds natural and idiomatic.

You could also hear:

• Foi um azar.
• Foi puro azar.

These are possible, but they feel slightly different:

• Foi azar = a simple, natural statement
• Foi um azar = It was an unlucky thing / a stroke of bad luck
• Foi puro azar = It was pure bad luck

So the version in your sentence is concise and very normal.

Ninguém means nobody or no one.

Even though it refers to zero people, grammatically it takes a singular verb in Portuguese:

• Ninguém teve culpa. = Nobody was to blame.

That is similar to English, where we also say:

• Nobody was...
• not Nobody were...

So:

• ninguém teve = correct
• ninguém tiveram = incorrect

Ter culpa is a very common Portuguese expression meaning:

• to be at fault
• to be to blame
• literally, to have blame/guilt

So:

• ninguém teve culpa = nobody was to blame

You could sometimes use ser culpado, but it often sounds stronger or more formal, and it can suggest actual guilt or responsibility in a heavier sense.

Compare:

• Ninguém teve culpa. = No one was at fault.
• Ninguém era culpado. = No one was guilty / culpable.

In this sentence, teve culpa is the most natural everyday phrasing.

This is another preterite vs. imperfect question.

• teve = had, as a completed fact
• tinha = had, in an ongoing/background/descriptive sense

Here, the speaker is making a conclusion about one specific event: the delay. So the preterite fits better:

• ninguém teve culpa pelo atraso = no one was to blame for the delay

If you used tinha, it would sound more like you were describing an ongoing state in the past rather than giving a final judgment about a completed incident.

Pelo is the contraction of:

• por + o = pelo

So:

• pelo atraso = for the delay / for the lateness

In this sentence, it means with regard to the delay or for causing the delay.

So:

• ninguém teve culpa pelo atraso = no one was to blame for the delay

Be careful: por can have many meanings in Portuguese, but here it is part of the idea of responsibility/blame connected to something.

Sometimes learners expect culpa do atraso, but culpa pelo atraso is the more natural structure when you mean blame for the delay.

Why?

Because here culpa is connected to responsibility for something that happened:

• ter culpa por/pelo atraso

Using de changes the relationship and may sound unnatural in this exact sentence.

A useful pattern to remember is:

• ter culpa por algo
• ter culpa pelo que aconteceu
• ter culpa pelo atraso

So pelo atraso is the structure you want here.

Yes. Mas simply means but.

It connects two ideas:

• Foi azar = It was bad luck
• mas ninguém teve culpa pelo atraso = but nobody was to blame for the delay

So the sentence contrasts:

1. something unfortunate happened
2. no person is responsible

That contrast is exactly what mas does.

That is close word-for-word, but it is not natural English.

A better English rendering is:

• It was bad luck, but nobody was to blame for the delay.
• It was just bad luck, but nobody was at fault for the delay.

This is a good example of how Portuguese often uses ter culpa, while English usually prefers:

• be to blame
• be at fault

It can mean both, depending on context.

• atraso = delay
• atraso = lateness

In this sentence, delay is the most natural translation:

• pelo atraso = for the delay

But in other contexts:

• Desculpe o atraso. = Sorry for being late / Sorry for the delay

So the exact English word depends on the situation.

It sounds natural and standard in Brazilian Portuguese. It is neither overly formal nor slangy.

That makes it a very useful model sentence.

Its tone is calm and matter-of-fact:

• Foi azar = it was unfortunate
• ninguém teve culpa = no one is being blamed

You could hear something like this in everyday conversation, at work, or in a polite explanation.

Yes. Foi má sorte is understandable and natural too.

Both mean It was bad luck, but there is a slight difference in feel:

• Foi azar = very common, compact, idiomatic
• Foi má sorte = also correct, maybe a little more transparent for learners because it matches English more closely

In everyday Brazilian Portuguese, azar is extremely common, so it is worth learning well.