Przeciwnik oszukuje.

Przeciwnik is a noun, and here it is in the nominative singular because it is the subject of the sentence.

A few useful details:

• dictionary form: przeciwnik
• gender: masculine
• meaning range: opponent, adversary, rival

In this sentence, przeciwnik is simply the one performing the action.

Because Polish present tense often covers both meanings that English separates:

• he cheats
• he is cheating

So Przeciwnik oszukuje can describe:

• a habitual action: the opponent cheats
• an ongoing action right now: the opponent is cheating

The exact meaning depends on context.

The infinitive is oszukiwać, which is the imperfective verb.

So:

• oszukiwać = to cheat / to be cheating / to deceive
• oszukuje = he/she/it cheats, is cheating

This is the 3rd person singular present tense form.

Because oszukuje is the 3rd person singular present form of oszukiwać.

A useful mini-pattern is:

• ja oszukuję = I cheat / am cheating
• ty oszukujesz = you cheat / are cheating
• on/ona/ono oszukuje = he/she/it cheats / is cheating

So the -uje ending tells you the subject is he/she/it (or a singular noun like przeciwnik).

It comes from the imperfective verb oszukiwać.

That matters because imperfective verbs are used for:

• ongoing actions
• repeated actions
• general facts

So Przeciwnik oszukuje suggests something like:

• the opponent is cheating right now
• the opponent cheats in general
• the opponent is engaged in cheating as a process

The perfective partner is usually oszukać, which focuses on a completed act, more like to cheat / deceive successfully, to trick in a completed sense.

For example:

• Przeciwnik oszukał sędziego. = The opponent deceived the referee.

Because Polish has no articles like English the and a/an.

So przeciwnik can mean:

• the opponent
• an opponent

Context tells you which one is intended.

That is completely normal in Polish.

Yes, it can be used without an object.

In Polish, oszukiwać can mean simply:

• to cheat
• to act dishonestly

So Przeciwnik oszukuje is a complete sentence.

If you want to say who is being deceived, you can add an object, for example:

• Przeciwnik oszukuje sędziego. = The opponent is deceiving the referee.
• Przeciwnik oszukuje graczy. = The opponent is cheating the players.

But the object is not required.

Yes. The verb oszukiwać can cover both ideas:

• to cheat
• to deceive
• to trick

Which English word is best depends on context.

For example:

• in a game or competition, cheating is often the best translation
• in a personal or psychological context, deceiving may fit better

So this verb is a little broader than just one English word.

No, Polish word order is fairly flexible.

Przeciwnik oszukuje is the most neutral order: subject + verb.

But you may also hear:

• Oszukuje przeciwnik.

That alternative order is possible, but it sounds marked and would usually depend on context, emphasis, or contrast.

For example, it might suggest something like:

• It’s the opponent who is cheating
• or a dramatic correction of what someone assumed

So the given order is the normal, neutral one.

Because the noun itself is singular, and the verb agrees with it:

• przeciwnik = singular
• oszukuje = 3rd person singular

If it were plural, you would have:

• Przeciwnicy oszukują. = The opponents are cheating.

So both the noun and the verb show singular vs plural.

In the present tense, the verb form would usually stay the same in 3rd person singular:

• Przeciwniczka oszukuje. = The female opponent is cheating.

So:

• masculine singular: oszukuje
• feminine singular: oszukuje
• neuter singular: oszukuje

In the present tense, Polish verbs do not show gender. Gender becomes much more visible in the past tense, for example:

• Przeciwnik oszukiwał.
• Przeciwniczka oszukiwała.

A rough guide is:

• prze- sounds somewhat like pshe
• ciw here sounds close to chiv
• -nik is like neek

A rough English approximation of przeciwnik is:

pshe-CHIV-neek

That said, English-style approximations are never perfect.

A few important sound notes:

• rz is usually pronounced like the zh sound in measure
• cz is like ch, but here you have eciw, where ci before a vowel gives a soft ć-like sound
• Polish consonant clusters are tighter and cleaner than in English

The stress is on the penultimate syllable:

• prze-CIW-nik

A rough approximation is:

o-shoo-KOO-ye

Useful sound notes:

• sz sounds like sh
• u sounds like oo
• je at the end is roughly ye

Stress in Polish is usually on the second-to-last syllable, so here the stress is on:

• o-szu-KU-je

It is neutral standard Polish.

Both words are normal, everyday vocabulary, and the sentence would fit many contexts:

• sports
• games
• debates
• arguments
• stories

It does not sound especially formal or slangy.

Yes, but then the meaning becomes more dependent on context.

Polish often omits subject pronouns, and sometimes even the noun subject if it is already clear. So:

• Oszukuje.

can mean:

• He/She is cheating
• He/She cheats

But if you want to make clear that it is the opponent, then keeping przeciwnik is natural and helpful.

The plural is:

Przeciwnicy oszukują.

Changes:

• przeciwnik → przeciwnicy = opponents
• oszukuje → oszukują = cheat / are cheating

So the sentence now means The opponents are cheating or Opponents cheat, depending on context.