Pro rizikový sport potřebuji cestovní pojištění.

Pro usually means for in the sense of intended for, needed for, or in relation to something.

So in Pro rizikový sport potřebuji cestovní pojištění, pro rizikový sport means for a risky / high-risk sport.

It sounds natural because the insurance is being described as something needed for that purpose/activity.

A very natural English restructuring is:

• I need travel insurance for a risky sport.

Pro takes the accusative case.

That is why rizikový sport is in the accusative.

Here’s the useful part:
sport is a masculine inanimate noun, and in the singular accusative, masculine inanimate nouns usually look the same as the nominative.

So:

• nominative: rizikový sport
• accusative: rizikový sport

The form does not change here, even though the case does.

Because sport is masculine inanimate, and for that noun type, the accusative singular is usually identical to the nominative singular.

Compare:

• nominative: ten sport
• accusative: vidím ten sport

So after pro, you still get:

• pro rizikový sport

If this were a masculine animate noun, you would usually see a different accusative form.

The adjective has to agree with the noun it describes.

Here:

• sport = masculine inanimate, singular, accusative
• so the adjective must match that

For masculine inanimate singular accusative, the adjective ending is the same as in the nominative:

• rizikový sport

So the adjective and noun match in:

• gender
• number
• case

Rizikový means risky, high-risk, or involving risk.

In this sentence, it suggests a sport that may require special insurance coverage because it is considered more dangerous than ordinary activities.

Depending on context, English translations could be:

• risky sport
• high-risk sport
• sometimes extreme sport if that is the intended real-world meaning

But grammatically, rizikový itself means risky / high-risk, not automatically extreme.

Yes. Both are correct.

• potřebuji = more standard / formal / careful
• potřebuju = very common in everyday speech

So both of these are fine:

• Pro rizikový sport potřebuji cestovní pojištění.
• Pro rizikový sport potřebuju cestovní pojištění.

If you are learning standard Czech, potřebuji is a very good form to know and use.

Potřebuji is the 1st person singular present tense of potřebovat = to need.

So:

• potřebuji = I need

Some useful forms:

• potřebuji = I need
• potřebuješ = you need
• potřebuje = he/she/it needs
• potřebujeme = we need
• potřebujete = you need / you all need
• potřebují = they need

This is a noun phrase meaning travel insurance.

• pojištění = insurance
• cestovní = travel

The adjective cestovní agrees with pojištění.

Pojištění is neuter singular, and in the accusative singular, neuter nouns usually look the same as in the nominative. So:

• nominative: cestovní pojištění
• accusative: cestovní pojištění

That is why the whole phrase stays in this form after potřebuji.

Pojištění is neuter.

A good clue is the ending -í, which is common in some neuter nouns, especially verbal nouns.

You can see the neuter clearly with demonstratives:

• to pojištění = that insurance

Because it is neuter singular, related words match it accordingly:

• cestovní pojištění

Not exactly.

• pojištění = insurance as a general concept, policy, or coverage
• pojistka = often insurance policy, policy document, or sometimes more colloquially a specific insurance product

In this sentence, cestovní pojištění is the most natural choice for travel insurance.

If you said cestovní pojistka, it could sound more like:

• a travel insurance policy
• the actual policy/document

But cestovní pojištění is the standard phrase learners should know.

Because Czech has no articles.

So Czech does not normally distinguish grammatically between:

• a risky sport
• the risky sport

The meaning is understood from context.

That means:

• rizikový sport can mean a risky sport or the risky sport
• cestovní pojištění can mean travel insurance, some travel insurance, or the travel insurance, depending on context

No, Czech word order is fairly flexible.

This sentence is perfectly natural:

• Pro rizikový sport potřebuji cestovní pojištění.

But you could also say:

• Potřebuji cestovní pojištění pro rizikový sport.

That version may feel a bit more neutral to many learners because it is closer to English order:

• I need travel insurance for a risky sport.

The original version puts pro rizikový sport first, which can give it a slight sense of topic or emphasis:

• As for a risky sport, I need travel insurance.

So both are possible; the difference is mainly about information structure and emphasis.

Usually, pro is the better choice here.

• pro = for, intended for, needed for
• na often has meanings like onto, for in some set expressions, or for an event/purpose in a different way

With insurance in this sentence, pro sounds natural because you mean:

• the insurance is needed for that activity

So:

• pro rizikový sport = natural

Using na here would not be the standard choice.

Yes, it is singular here.

In Czech, singular can sometimes be used in a fairly general way, especially when talking about a type of activity. So pro rizikový sport can be understood as for doing a risky sport / for a high-risk sport activity.

If you specifically wanted the plural, you could say:

• pro rizikové sporty = for risky sports

That might be useful if you are speaking more generally about several kinds of high-risk sports.

A simple pronunciation guide:

• Pro ≈ pro
• rizikový ≈ RI-zi-ko-vee
• sport ≈ sport
• potřebuji ≈ PO-trzhe-boo-yi
• cestovní ≈ TES-to-vnee
• pojištění ≈ PO-yi-sh-tye-nyee

A few key points:

• Czech stress is usually on the first syllable of each word.
• ř in potřebuji is a special Czech sound; learners often approximate it at first.
• j is pronounced like English y.
• š is like English sh.
• č would be like ch in church (not in this sentence, but useful to know).

A very easy version to remember is:

• Potřebuji cestovní pojištění pro rizikový sport.

It maps neatly onto English:

• I need travel insurance for a risky sport.

The original sentence is also correct and natural, but for memorizing structure, many learners find this order simpler:

1. Potřebuji = I need
2. cestovní pojištění = travel insurance
3. pro rizikový sport = for a risky sport

Three especially useful things:

1. Pro + accusative

   • pro rizikový sport

2. Agreement of adjective + noun

   • rizikový sport
   • cestovní pojištění

3. Flexible word order

   • Pro rizikový sport potřebuji cestovní pojištění.
   • Potřebuji cestovní pojištění pro rizikový sport.

If you understand those three points, you understand most of the grammar in this sentence.