Chci vypovědět smlouvu na dobu neurčitou; výpovědní lhůta je měsíc.

This is a very common Czech pattern:

• chtít = to want
• vypovědět = to terminate / to give notice to
• chci vypovědět = I want to terminate / give notice to

So Czech, like English, often uses want + infinitive.

A quick mini-pattern:

• Chci odejít. = I want to leave.
• Chci to změnit. = I want to change it.
• Chci vypovědět smlouvu. = I want to terminate the contract.

The form chci is 1st person singular present of chtít.

This is mainly about aspect.

• vypovědět is perfective
• vypovídat is imperfective

In this sentence, the speaker wants to perform one complete legal act: terminate the contract. Czech usually prefers the perfective infinitive after chtít, when you mean a completed result.

So:

• Chci vypovědět smlouvu. = I want to terminate the contract.
  → focus on completing the act

By contrast, vypovídat would usually suggest an ongoing, repeated, or process-like action, which is not the normal idea here.

Because smlouva is the direct object of vypovědět, so it goes into the accusative case.

• nominative: smlouva
• accusative: smlouvu

You can think of it like this:

• vypovědět co? → smlouvu

This is very typical in Czech: the thing affected by the verb often goes into the accusative.

This is a fixed and very common legal/business phrase.

Breakdown:

• na = for / for a period of
• dobu = accusative singular of doba (period, term)
• neurčitou = accusative singular feminine adjective agreeing with dobu

So grammatically:

• na dobu = for a period
• na dobu neurčitou = for an indefinite period

The adjective neurčitou matches dobu, not smlouvu.

That is important: this phrase describes the duration/term, not the noun contract directly at the grammar level.

Because it agrees with dobu, which is:

• feminine
• singular
• accusative

The adjective has to match that.

Comparison:

• nominative: neurčitá doba
• accusative: na neurčitou dobu or na dobu neurčitou

So -ou is the expected feminine singular accusative ending for this adjective pattern.

Because na dobu neurčitou is the standard Czech expression for legal or contractual indefinite duration.

It is the normal collocation in formal contexts, especially with:

• smlouva na dobu neurčitou = contract for an indefinite period
• pracovní poměr na dobu neurčitou = employment for an indefinite period

A phrase like bez konce would sound much less natural in this kind of official/legal statement.

These are related, but not the same thing.

• výpověď = notice / termination notice / resignation notice, depending on context
• výpovědní lhůta = notice period

So:

• dát výpověď = to give notice / resign / terminate
• výpovědní lhůta = the period between giving notice and the actual end

The adjective výpovědní means something like relating to notice/termination.

So in the sentence:

• výpovědní lhůta je měsíc = the notice period is one month

After být (to be), Czech often uses the nominative for predicate nouns, especially in modern everyday Czech.

So:

• Výpovědní lhůta je měsíc.

Here měsíc is nominative.

You may also encounter instrumental after být in some contexts, but with statements of this type, nominative is the normal and natural choice.

Compare:

• To je problém.
• Je to chyba.
• Lhůta je měsíc.

Because in Czech, when stating duration, measure, or amount in this kind of sentence, the numeral one is often omitted if it is obvious.

So:

• je měsíc = it is a month / it is one month

Adding jeden is possible for emphasis or contrast, but it is not necessary.

Compare:

• Výpovědní lhůta je měsíc. = The notice period is one month.
• Výpovědní lhůta je jeden měsíc, ne dva. = The notice period is one month, not two.

Often yes, but the nuance depends on context.

• dát výpověď is a very common phrase, especially with jobs, rentals, contracts, etc.
• vypovědět smlouvu is a bit more explicit and legal/formal: it directly says terminate the contract

So:

• Chci dát výpověď.
  = I want to give notice.
  This can be slightly broader or more context-dependent.

• Chci vypovědět smlouvu.
  = I want to terminate the contract.
  This is very precise.

In legal or administrative language, vypovědět smlouvu is often preferred for clarity.

Yes, functionally it works that way.

Even though the Czech structure is literally more like:

• contract for an indefinite period

the whole phrase behaves like the equivalent of an indefinite/open-ended contract.

This is extremely common in Czech. The contract is identified by the term it is concluded for:

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

This is the most neutral and natural word order.

Basic structure:

• Chci = I want
• vypovědět = to terminate
• smlouvu = contract
• na dobu neurčitou = of indefinite duration / for an indefinite period

Czech word order is flexible, but the neutral order usually puts the phrase right after the noun it belongs with:

• smlouvu na dobu neurčitou

You could rearrange things in some contexts, but this version is the clearest and most standard.

Because the sentence contains two closely related independent statements:

• Chci vypovědět smlouvu na dobu neurčitou
• výpovědní lhůta je měsíc

A semicolon links them more strongly than a full stop, but keeps them more separate than a comma.

In English, this is similar to:

• I want to terminate an open-ended contract; the notice period is one month.

You could also split them into two sentences in Czech, and that would be fine too.

Yes, it sounds fairly formal/administrative/legal, especially because of expressions like:

• vypovědět smlouvu
• na dobu neurčitou
• výpovědní lhůta

These are standard in contracts, HR, housing, and business communication.

In everyday conversation, people might use shorter or less formal phrasing depending on context, but this sentence is completely natural in official situations.

They are opposites.

• na dobu neurčitou = for an indefinite period, with no fixed end date
• na dobu určitou = for a fixed period, with a defined end date

For example:

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

This contrast is extremely important in Czech legal and employment vocabulary.