Smlouva na dobu určitou je dlouhá.

Smlouva means contract or agreement. It is a feminine noun.

That matters because adjectives and some other words in Czech have to agree with the noun’s gender. In this sentence, both the structure of the sentence and the adjective dlouhá reflect the fact that smlouva is feminine.

Because dlouhá agrees with smlouva.

• smlouva = feminine singular
• so the adjective must also be feminine singular
• therefore: dlouhá

Compare:

• dlouhý = masculine singular
• dlouhá = feminine singular
• dlouhé = neuter singular

Even though dlouhá comes after je, it still agrees with the subject smlouva.

It is in the nominative singular because it is the subject of the sentence.

So the basic structure is:

• Smlouva na dobu určitou = the subject
• je dlouhá = the predicate

In other words, the fixed-term contract is what is long.

Literally, it means something like for a definite period or for a fixed period.

Word by word:

• na = for
• dobu = period / time span
• určitou = definite / fixed / specific

As a whole, smlouva na dobu určitou is the standard expression for a fixed-term contract.

Because the preposition na here requires the accusative when it means for a period of time.

The noun is:

• nominative: doba
• accusative: dobu

So:

• na dobu určitou = for a fixed period

This is a very common Czech pattern with expressions of duration.

Because určitou agrees with dobu.

• doba is feminine singular
• after na, it becomes accusative singular: dobu
• the adjective must match it: určitou

So both words are feminine singular accusative:

• dobu
• určitou

That is a very good question. Normally, yes, Czech adjectives often come before the noun. But na dobu určitou is a fixed legal/official expression.

There is an important difference between:

• na dobu určitou = for a fixed term / fixed-term
• na určitou dobu = for a certain period of time

So the order in your sentence is not random. Na dobu určitou is the established phrase used especially in legal and employment language, often contrasted with na dobu neurčitou.

Yes. Je is the 3rd person singular of být (to be), and in a sentence like this it is normally required.

So:

• Smlouva ... je dlouhá. = The contract is long.

Czech does not usually drop the present tense of to be in standard sentences like this.

Czech has no articles, so there is no direct equivalent of a or the.

That means Smlouva na dobu určitou je dlouhá can mean:

• A fixed-term contract is long
• The fixed-term contract is long

The exact meaning depends on context.

If Czech wants to make it more specific, it can use words like:

• ta smlouva = that/the contract
• jedna smlouva = one/a certain contract

Yes, Czech word order is fairly flexible. The version you have is a neutral, normal order:

• Smlouva na dobu určitou je dlouhá.

But other orders are possible for emphasis, for example:

• Dlouhá je smlouva na dobu určitou.
• Smlouva je dlouhá.

The meaning stays similar, but the emphasis changes. For learners, the original order is the safest and most natural one to use.

The opposite is na dobu neurčitou.

So:

• smlouva na dobu určitou = fixed-term contract
• smlouva na dobu neurčitou = open-ended / indefinite-term contract

This pair is extremely common in Czech, especially in job and rental contexts.

Grammatically, dlouhá describes smlouva, not doba.

So the sentence most directly says that the contract is long. Depending on context, that could mean:

• the text/document is lengthy, or
• the contract lasts a long time

If you want to make the idea of duration clearer, Czech would often use a more explicit wording, for example:

• Je na dlouhou dobu. = It is for a long period.
• Trvá dlouho. = It lasts a long time.

So your sentence is correct, but context determines exactly what kind of long is meant.

Yes. Smlouva is often translated as contract, but it can also mean agreement, depending on context.

In legal or employment situations, contract is usually the best translation. In broader contexts, agreement may also work.

So in this sentence, because of na dobu určitou, fixed-term contract is the most natural English rendering.