Hudebník hraje.

It is in the nominative singular. That is the basic dictionary form and the form typically used for the subject of the sentence.

So in Hudebník hraje, hudebník is the person doing the action.

Czech normally has no articles. So hudebník can mean:

• a musician
• the musician

The exact meaning depends on context. English must choose, but Czech usually does not.

Hraje is the 3rd person singular present tense of the verb hrát.

Here it can mean:

• plays
• is playing

Czech present tense often covers both the simple present and the present continuous, so context tells you which is meant.

Yes.

Depending on context, it can mean:

• The musician plays — a general or habitual meaning
• The musician is playing — something happening now

Czech does not usually make this distinction with a different verb form the way English does.

Yes. The sentence is perfectly complete.

The verb hrát can be used without saying exactly what is being played. In that case it can simply mean that someone is playing music or performing.

If you want to add more detail, you can say for example:

• Hudebník hraje na kytaru. — The musician is playing the guitar.
• Hudebník hraje skladbu. — The musician is playing a piece.

A rough guide:

• Hudebník ≈ HOO-deb-neek
• hraje ≈ HRAH-ye

A few useful points:

• Czech stress is usually on the first syllable: HUdebník, HRAje
• í is a long vowel
• j is pronounced like English y in yes
• Czech h is a real pronounced consonant, not silent

Because Czech verb forms already show the person and number.

Hraje tells you it is 3rd person singular: he/she/it plays.

Since the subject is already given as hudebník, adding a pronoun would usually be unnecessary.

Grammatically, hudebník is a masculine noun and normally refers to a male musician.

The usual feminine form is:

• hudebnice — female musician

However, in some contexts masculine forms can be used more generally, depending on style and situation. But if you clearly mean a woman, hudebnice is the normal choice.

Yes, Czech word order is more flexible than English word order.

The neutral, ordinary version is:

• Hudebník hraje.

You might also see:

• Hraje hudebník.

But that changes the emphasis. It can sound marked, poetic, or context-dependent, and it may be used if the speaker wants to focus on the action first or if it is part of a question-like structure.

So for a basic statement, Hudebník hraje is the safest choice.

You add ne- to the verb:

• Hudebník nehraje. — The musician is not playing.

This is a very common pattern in Czech: negation is usually formed directly on the verb.

A simple way is with intonation:

• Hudebník hraje? — Is the musician playing?

You can also change word order:

• Hraje hudebník?

Both are possible. In speech, intonation is very important.

The infinitive is hrát — to play.

Yes, it is worth learning the present tense forms:

• hraju / hraji — I play / am playing
• hraješ — you play
• hraje — he/she/it plays
• hrajeme — we play
• hrajete — you plural / formal play
• hrají / hrajou — they play

For your sentence, the important part is that hraje matches a singular subject like hudebník.

Very often Czech uses hrát na plus the instrument.

For example:

• Hudebník hraje na klavír. — The musician plays the piano.
• Hudebník hraje na kytaru. — The musician plays the guitar.
• Hudebník hraje na housle. — The musician plays the violin.

So Hudebník hraje is the basic sentence, and then you can add more information after it.