Požar je veliki rizik.

Serbian does not have articles, so there is no direct equivalent of English a/an or the.

That means Požar je veliki rizik can be understood from context, not from an article. Depending on the situation, English might express it as:

• Fire is a big risk
• A fire is a big risk
• sometimes even The fire is a big risk

Serbian leaves that distinction to context.

It can mean either, depending on context.

In this sentence, the most likely reading is fire in general as a general danger or hazard. Serbian often uses a bare singular noun this way.

So here požar is probably not one specific fire, but the concept of fire as a risk.

Je is the 3rd person singular present form of biti (to be), and it is a clitic in this form. In Serbian, clitics usually go in the second position of the clause.

So:

• Požar = first element
• je = clitic in second position
• veliki rizik = the rest of the sentence

That is why Požar je veliki rizik is the normal order.

In a normal sentence, yes, you should include je.

Unlike Russian, Serbian normally keeps the present-tense form of to be in sentences like this. So:

• Požar je veliki rizik = normal, correct sentence
• Požar veliki rizik = sounds incomplete, like a headline, note, or very nonstandard speech

For a learner, it is best to always include je here.

Both nouns are in the nominative singular.

• požar = nominative singular, masculine
• rizik = nominative singular, masculine

Why?

• požar is the subject
• rizik is the predicate noun after je

So the structure is basically:

• Požar = subject
• je = is
• veliki rizik = predicate noun phrase

Because veliki agrees with rizik, and rizik is:

• masculine
• singular
• nominative

So the adjective must also be masculine singular nominative:

• veliki rizik

If the noun were feminine, you would get velika.
If it were neuter, you would get veliko.

For example:

• velika opasnost = big danger
• veliko pitanje = big question

It describes rizik, not požar.

The phrase is:

• veliki rizik = big risk

So the sentence means that fire is a big risk, not that the fire itself is big.

If you wanted to say that the fire is big, you would say something like:

• Požar je velik.
• or sometimes Požar je veliki.

But in your sentence, veliki clearly belongs to rizik.

Yes, you may also encounter velik rizik, but veliki rizik is the safest and most neutral choice for learners.

In modern Serbian, the longer form veliki is very common before a noun. The shorter form velik also exists, but it can sound more literary, stylistically marked, or simply less neutral depending on the speaker and context.

So:

• veliki rizik = very standard, natural, safe choice
• velik rizik = possible, but less predictable for learners

Yes, it is correct and understandable.

That said, depending on context, Serbian speakers might also say:

• Požar predstavlja veliki rizik. = more formal
• Požar je velika opasnost. = if the idea is more danger than risk

So Požar je veliki rizik is fine, but there are other natural ways to express a similar idea.

A rough English-friendly pronunciation is PO-zhar.

A few helpful points:

• ž sounds like the s in measure or the g in genre
• the r is pronounced clearly; in Serbian it is usually tapped or rolled more than in English
• both vowels are pronounced clearly: po-žar

So požar is roughly PO-zhar, not PO-jar and not PO-zar.