A műanyag szennyezett.

Here a means the, not English a/an.

In Hungarian, a/az is the definite article:

• a before a consonant: a műanyag
• az before a vowel: az alma

So A műanyag szennyezett. means The plastic is contaminated/dirty.

If you wanted a plastic in the indefinite sense, Hungarian would usually use egy.

Because Hungarian normally leaves out the verb to be in the present tense, third person singular, when the predicate is a noun or adjective.

So:

• A műanyag szennyezett. = The plastic is contaminated.

There is no separate word for is here, but the meaning is still complete and natural in Hungarian.

You do use forms of to be in other situations, for example:

• past: A műanyag szennyezett volt. = The plastic was contaminated.
• future: A műanyag szennyezett lesz. = The plastic will be contaminated.
• 1st/2nd person: Szennyezett vagyok. = I am contaminated/dirty.

Műanyag means plastic.

It is most often used for the material itself, but depending on context it can also refer to a plastic object or plastic substance under discussion.

A useful detail is that the word is built from:

• mű- = artificial / man-made
• anyag = material

So the word literally has the idea of artificial material.

In this sentence, it is functioning as a noun: the plastic.

Szennyezett is an adjective meaning something like:

• contaminated
• polluted
• dirty
• soiled

The best English choice depends on context.

It comes from the verb szennyez = to contaminate / to make dirty. So szennyezett has a participle-like feel: contaminated.

In A műanyag szennyezett., it is the predicate adjective: it tells you what state the plastic is in.

Good question. In Hungarian, adjectives come before a noun when they directly modify it:

• a szennyezett műanyag = the contaminated plastic

But in your sentence, szennyezett is not just modifying the noun inside a noun phrase. It is the predicate of the whole sentence:

• A műanyag szennyezett. = The plastic is contaminated.

So the structure is basically:

• A műanyag = the subject
• szennyezett = the predicate adjective

That is why the word order is different.

The stress is on the first syllable, as in Hungarian words generally:

• MŰanyag

A rough guide:

• mű has a long vowel similar to German ü, but held longer
• ny sounds like Spanish ñ or the ny in English canyon
• the whole word is roughly MŰ-anyag

So a rough English-friendly approximation is MYOO-onyog, but that is only approximate. The important things are:

• first-syllable stress
• long ű
• ny as a single sound

Yes. Hungarian word order is flexible, but changes the focus or emphasis.

The version you have:

• A műanyag szennyezett.

is a neutral statement: The plastic is contaminated.

If you say:

• Szennyezett a műanyag.

that puts more focus on szennyezett, as if emphasizing the condition: The plastic is contaminated / It’s contaminated, the plastic.

So both can be correct, but they are not used in exactly the same discourse situation.

No. Hungarian has no grammatical gender like many European languages do.

So:

• nouns are not masculine/feminine/neuter
• adjectives do not change for gender

That means szennyezett stays the same regardless of natural gender, because Hungarian grammar does not mark that kind of distinction.

What does matter is number. In the singular, you have:

• A műanyag szennyezett.

With a plural subject, the predicate adjective is plural:

• A műanyagok szennyezettek. = The plastics / plastic items are contaminated.

So there is no gender agreement, but number can matter.

Yes, it can, depending on context.

Hungarian often uses the definite article in places where English might use no article or a generic expression. So a műanyag can sometimes refer to plastic as a material in general, and in other contexts to the plastic already known from the conversation.

In this sentence by itself, the most straightforward reading is usually The plastic is contaminated, but context always helps decide exactly how specific it is.