Polovno vozilo nema ni ogrebotinu ni udubljenje.

Because vozilo is a neuter singular noun. In Serbian, adjectives must agree with the noun in gender, number, and case.

The adjective polovan changes like this in the singular:

• masculine: polovan
• feminine: polovna
• neuter: polovno

So with vozilo, you need polovno vozilo.

Vozilo means vehicle, so it is broader than auto or automobil, which mean car.

In contexts like ads, inspections, and official descriptions, Serbian often uses vozilo because it sounds a bit more general and formal. In everyday speech, many people would naturally say auto if they specifically mean a car.

Nema is the normal negative present-tense form of imati (to have) in the 3rd person singular.

Compare:

• ima = he/she/it has
• nema = he/she/it does not have

Likewise:

• imam / nemam
• imaš / nemaš
• imamo / nemamo

So Serbian does not use an English-style structure like does not have. It simply uses the negative form of the verb itself.

Yes, from an English point of view it looks like a double negative, but in Serbian this is completely normal. Serbian uses negative concord.

Here:

• nema = does not have
• ni ... ni = neither ... nor

So nema ni ogrebotinu ni udubljenje literally has both a negative verb and the paired ni ... ni structure. That is standard Serbian, not a mistake.

It means neither ... nor.

So:

• ni ogrebotinu ni udubljenje = neither a scratch nor a dent

The word ni is repeated before each item in the pair, just like English repeats neither / nor across two parts.

Because the two nouns belong to different genders and declension patterns.

• ogrebotina is a feminine noun
• udubljenje is a neuter noun

In this sentence they function as direct objects, so they appear in the accusative singular.

That gives:

• ogrebotina → ogrebotinu
• udubljenje → udubljenje

For many neuter nouns, the nominative and accusative singular are the same, so udubljenje does not change in form.

In this sentence, they are in the accusative singular.

That is why:

• ogrebotina becomes ogrebotinu
• udubljenje stays udubljenje

You may also encounter Serbian sentences where negation leads to genitive instead, especially in some styles or with some speakers. For example, you might also see:

• nema ni ogrebotine ni udubljenja

So there is some variation in real usage, but the sentence you were given uses the accusative.

Using the singular here gives the sense of not even one scratch and not even one dent.

So the sentence is emphasizing total absence:

• not a single scratch
• not a single dent

A plural version is also very common in Serbian, especially when speaking more generally:

• nema ogrebotina ni udubljenja = it has no scratches or dents

Both ideas are natural, but the singular can sound a bit more pointed or emphatic.

Because Serbian has no articles. There is no direct equivalent of English a / an / the used before nouns in ordinary grammar.

So:

• vozilo can mean a vehicle, the vehicle, or just vehicle
• ogrebotinu can mean a scratch
• udubljenje can mean a dent

The exact sense usually comes from context.

Yes, Serbian word order is more flexible than English word order, but the version you have is a very natural, neutral one:

• Polovno vozilo = subject
• nema = verb
• ni ogrebotinu ni udubljenje = coordinated object phrase

You can move parts around for emphasis, but the given order is the safest and most standard for a learner to use.