Dostava je danas nemoguća.

• Dostava = delivery. It is a noun, feminine, singular, and here it is in the nominative because it is the subject of the sentence.
• je = is. This is the 3rd person singular of biti (to be).
• danas = today. This is an adverb of time.
• nemoguća = impossible / not possible. This is an adjective and it agrees with dostava in gender, number, and case.

So the structure is basically:

[Subject] + [is] + [time adverb] + [predicate adjective]

= Delivery is today impossible → natural English: Delivery is impossible today.

Because nemoguća must agree with dostava.

• dostava is feminine singular
• so the adjective must also be feminine singular

Compare:

• nemoguć = masculine singular
• nemoguća = feminine singular
• nemoguće = neuter singular, or sometimes plural depending on context

Since dostava is feminine, Serbian uses:

• Dostava je nemoguća.

This kind of agreement is very important in Serbian.

Je is the present-tense form of biti (to be) for he/she/it is.

In this sentence, Serbian needs the copula is, just like English does:

• Dostava je nemoguća.
• Delivery is impossible.

So je links the subject dostava with the description nemoguća.

Normally, in a standard sentence like this, no.

You say:

• Dostava je danas nemoguća.

Not:

• Dostava danas nemoguća.

In some special styles—headlines, notes, or very compressed speech—the verb may sometimes be dropped, but for normal Serbian you should keep je.

Because Serbian word order is quite flexible, and adverbs like danas can move around.

The version:

• Dostava je danas nemoguća.

sounds natural and emphasizes the time condition: today it is impossible.

You could also hear:

• Dostava je nemoguća danas.
• Danas je dostava nemoguća.

These are all understandable, but they may sound slightly different in emphasis.

A very natural default version is:

• Dostava je danas nemoguća.

Yes, it is grammatically correct, but it sounds a bit less neutral in many contexts.

• Dostava je danas nemoguća. = more natural, smoother, more standard in everyday use
• Dostava je nemoguća danas. = puts danas later, which can make today feel a bit more contrastive or added on

Serbian often uses word order to shift emphasis rather than meaning.

Because Serbian has no articles like a, an, or the.

So dostava can mean:

• delivery
• the delivery
• a delivery

The exact meaning depends on context.

In this sentence, English will usually translate it as:

• Delivery is impossible today or
• The delivery is impossible today depending on the situation.

They are very close in meaning:

• Dostava je nemoguća.
• Dostava nije moguća.

Both mean delivery is not possible.

But there can be a small stylistic difference:

• nemoguća is a single adjective meaning impossible
• nije moguća is more literally is not possible

Often they are interchangeable.
The first can feel slightly more compact or definite; the second can feel a bit more analytical.

Because it is the subject of the sentence.

In Serbian, the subject of a sentence is usually in the nominative:

• Dostava je nemoguća.

If dostava had another role in the sentence, it might appear in another case. For example:

• Čekam dostavu. = I am waiting for the delivery.
  Here dostavu is in the accusative.

But in Dostava je danas nemoguća, it is the thing being talked about, so nominative is used.

A good clue is its ending:

• nouns ending in -a are often feminine in Serbian

So dostava is feminine, and that is confirmed by the adjective form:

• nemoguća

Other feminine examples:

• poruka je važna = the message is important
• situacija je teška = the situation is difficult

This is not a perfect rule for every noun, but it works very often.

Both can relate to delivery, but they are not always used in exactly the same way.

• dostava often means delivery in everyday practical contexts, especially bringing something to someone

  • food delivery
  • package delivery
  • home delivery

• isporuka often sounds more formal, logistical, or business-like

  • shipment
  • supply delivery
  • commercial delivery

In a sentence like this, Dostava je danas nemoguća sounds very natural for ordinary customer-facing situations.

A simple approximation for English speakers is:

neh-moh-GOO-chya

A few notes:

• ne- as in neh
• mo- as in moh
• guć contains ć, a soft sound somewhat like a very soft ch
• -a is a short open a

The letter ć is softer than č.
English does not have a perfect equivalent, so learners often approximate it with ty or a soft ch.

Yes. That is a very natural interpretation in context.

Even though the Serbian sentence literally uses impossible, in real usage it often communicates:

• Delivery is not possible today
• Delivery cannot be made today
• We cannot deliver today

So the meaning in English may be adjusted depending on the situation, even if the Serbian wording stays the same.

Yes, and it means something slightly different in tone.

• Dostava je danas nemoguća. = Delivery is impossible today / Delivery is not possible today
• Nema dostave danas. = There is no delivery today

The second one sounds more direct and factual: there simply will be no delivery.
The first one describes the situation as impossible or not possible.

Both are natural, but the nuance is a little different.