Nemoj preskočiti doručak prije ispita.

Nemoj is the usual way to make a negative command in Croatian when speaking to one person informally.

So:

• Preskoči doručak. = Skip breakfast.
• Nemoj preskočiti doručak. = Don’t skip breakfast.

This pattern is very common:

• Nemoj kasniti. = Don’t be late.
• Nemoj zaboraviti. = Don’t forget.

For other people, the forms change:

• nemoj = don’t... (to one person, informal)
• nemojmo = let’s not...
• nemojte = don’t... (to more than one person, or formal)

After nemoj / nemojte / nemojmo, Croatian normally uses the infinitive.

So the structure is:

• nemoj + infinitive

Examples:

• Nemoj ići. = Don’t go.
• Nemoj zaboraviti. = Don’t forget.
• Nemoj preskočiti doručak. = Don’t skip breakfast.

This is one of the most important command patterns to learn.

This is about aspect, which is very important in Croatian.

• preskočiti = perfective
• preskakati = imperfective

In this sentence, preskočiti means a single completed act: to skip breakfast on that occasion.

With negative commands, Croatian often uses the perfective infinitive to warn against a specific action:

• Nemoj preskočiti doručak. = Don’t skip breakfast.

If you used preskakati, it would suggest repeated or habitual skipping:

• Nemoj preskakati doručak. = Don’t keep skipping breakfast / Don’t make a habit of skipping breakfast.

So both are possible in some contexts, but they do not mean exactly the same thing.

Because doručak is the direct object of preskočiti, and here it is in the accusative case.

For many masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: doručak
• accusative: doručak

That is why the form does not change.

Compare:

• Vidim stol. = I see the table.
• Kupujem kruh. = I’m buying bread.
• Preskočiti doručak. = To skip breakfast.

Because prije means before, and it requires the noun after it to be in the genitive case.

So:

• prije
  • genitive

Here:

• ispit = exam
• genitive singular = ispita

That gives:

• prije ispita = before the exam

Other examples:

• prije škole = before school
• prije ručka = before lunch
• prije puta = before the trip

Ispita is genitive singular of ispit.

You know it is genitive because the preposition prije requires the genitive.

Basic forms:

• nominative: ispit = exam
• genitive: ispita = of the exam / before the exam, depending on context

So in this sentence:

• prije ispita = before the exam

This is a very common pattern, so it is worth memorizing together:

• poslije sastanka = after the meeting
• tijekom dana = during the day
• prije ispita = before the exam

The given word order is the most natural and neutral:

• Nemoj preskočiti doručak prije ispita.

But Croatian word order is more flexible than English, so other versions are possible for emphasis.

For example:

• Prije ispita nemoj preskočiti doručak.
  This emphasizes before the exam.

• Doručak nemoj preskočiti prije ispita.
  Grammatically possible, but less neutral and more marked.

In normal speech, the original sentence is the best choice.

Normally, no. That is not the standard way to make a negative command in Croatian.

Croatian usually does not form negative imperatives by simply putting ne in front of the positive imperative. Instead, it uses:

• nemoj + infinitive

So:

• Preskoči doručak. = Skip breakfast.
• Nemoj preskočiti doručak. = Don’t skip breakfast.

This is different from English, where you can simply add don’t before the verb.

Nemoj is informal singular — used when speaking to one person you address with ti.

If you need the formal or plural form, use:

• Nemojte preskočiti doručak prije ispita.

That can mean:

• speaking to more than one person
• speaking politely/formally to one person

And if you want let’s not, use:

• Nemojmo preskočiti doručak prije ispita.

A simple pronunciation guide is:

• Nemoj ≈ NEH-moy
• preskočiti ≈ preh-SKOH-chee-tee
• doručak ≈ doh-ROO-chak
• prije ≈ PREE-yeh
• ispita ≈ EE-spee-tah

A few useful sound notes:

• č sounds roughly like ch in chocolate
• j sounds like y in yes
• ije in prije is pronounced something like ee-ye

So the whole sentence sounds approximately like:

NEH-moy preh-SKOH-chee-tee doh-ROO-chak PREE-yeh EE-spee-tah

Yes, depending on context.

You could say:

• Nemoj preskočiti doručak. = Don’t skip breakfast.
• Nemoj preskočiti prije ispita. = This sounds incomplete, because preskočiti usually needs an object here.
• Prije ispita nemoj preskočiti doručak. = Before the exam, don’t skip breakfast.

So:

• doručak is important because it tells you what not to skip
• prije ispita adds the time reference

The full sentence is the clearest and most natural version.