Zaposleni ima ugovor o radu.

In this sentence, zaposleni is singular: Zaposleni ima ugovor o radu.

You can tell because the verb is ima, which is 3rd person singular (has).

The confusing part is that zaposleni can also be plural in other contexts. For example:

• Zaposleni imaju ugovor o radu. = The employees have an employment contract.

So zaposleni can be either singular or plural, and the verb usually makes it clear.

Here it functions as a noun, meaning employee.

Originally, zaposleni comes from an adjective/participle meaning employed. But Serbian often uses adjective forms as nouns when the meaning is clear.

So:

• zaposleni čovek = an employed man
• zaposleni = an employee

This is very common in Serbian.

Ima is the 3rd person singular present tense of imati = to have.

The forms are:

• ja imam = I have
• ti imaš = you have
• on/ona/ono ima = he/she/it has

Since zaposleni is singular, the verb must also be singular:

• Zaposleni ima... = The employee has...

Because ugovor is a masculine inanimate noun, and in Serbian, the accusative singular of masculine inanimate nouns is usually the same as the nominative singular.

So:

• nominative: ugovor
• accusative: ugovor

That is why you see:

• Zaposleni ima ugovor.

If it were a masculine animate noun, the accusative would usually look different.

Radu is in the locative singular.

The preposition o usually means about / concerning, and with that meaning it takes the locative:

• o radu = about work / concerning work

The noun is:

• rad = work
• locative singular: radu

So ugovor o radu literally means something like contract about work or contract concerning work, but in natural English it means employment contract.

Yes, very much so. Ugovor o radu is the normal and standard Serbian expression for employment contract.

Even though an English speaker might want to build something like work contract, Serbian strongly prefers ugovor o radu in legal and everyday usage.

You may understand radni ugovor, but ugovor o radu is the idiomatic form.

Serbian has no articles.

So zaposleni can mean:

• an employee
• the employee

And ugovor can mean:

• a contract
• the contract

The exact meaning depends on context.

So Zaposleni ima ugovor o radu could mean:

• The employee has an employment contract
• An employee has an employment contract

In practice, the surrounding context tells you which one is intended.

In this exact form, zaposleni is grammatically masculine singular.

For a specifically female employee, you would usually say:

• Zaposlena ima ugovor o radu.

However, in formal, administrative, or general statements, masculine forms are sometimes used in a broader or generic way, depending on style and context.

So if you want to be clearly feminine, use zaposlena.

Yes, Serbian word order is more flexible than English word order.

The neutral order here is:

• Zaposleni ima ugovor o radu.

That is the most natural basic version.

You can change the order for emphasis, but it may sound marked or stylistically different. For example:

• Ugovor o radu ima zaposleni.
  This puts more focus on ugovor o radu, but it is less neutral.

For learners, it is best to stick with the standard order:

• subject + verb + object

Both can refer to someone who works, but they are not exactly the same.

• zaposleni = employee, someone who is employed
• radnik = worker, often more connected with labor/work as such

Zaposleni is more neutral and fits very well in administrative, business, and legal language.

Since ugovor o radu is also a formal/legal expression, zaposleni is a very natural match here.

Because Serbian does not need a subject pronoun when the subject is already stated.

Here, the subject is explicitly given:

• Zaposleni = the employee

So there is no reason to add on or ona.

In fact, adding a pronoun here would usually sound unnecessary unless you wanted special emphasis.

That depends on the variety of the language.

• zaposleni is the normal and very common form in Serbian
• zaposlenik is much more typical of Croatian

A Serbian learner should usually prefer zaposleni.

So for Serbian, this sentence is best as:

• Zaposleni ima ugovor o radu.