إطار النظارة نظيف.

A fully vocalized version is:

إِطارُ النَّظَّارَةِ نَظيفٌ

A careful pronunciation would be roughly:

ʾiṭāru n-naẓẓārati naẓīfun

A few notes:

• إطارُ = ʾiṭāru
• النظارةِ = an-naẓẓārati / n-naẓẓārati in connected speech
• نظيفٌ = naẓīfun

Because ن is a sun letter, the ل of الـ is not pronounced clearly here, so النظارة sounds like an-naẓẓāra... rather than al-naẓẓāra...

In Arabic, present-tense nominal sentences usually do not use a separate word for is / are.

So:

• إطار النظارة نظيف. literally looks like:
• The glasses frame clean.

But it means:

• The frame of the glasses is clean.

This is completely normal in Arabic. If you wanted was, then Arabic would use a verb such as كان.

This is an iḍāfa construction, often called a genitive construction or construct phrase.

It works like this:

• إطار = frame
• النظارة = the glasses / the eyeglasses

Together:

• إطار النظارة = the frame of the glasses
• more naturally in English: the eyeglass frame or the glasses frame

Arabic often expresses of relationships by simply putting two nouns next to each other, without a separate word for of.

In an iḍāfa construction, the first noun usually does not take الـ.

So Arabic says:

• إطار النظارة

not:

• الإطار النظارة

In this structure:

• the first noun is the thing being possessed or specified: إطار = frame
• the second noun tells what it belongs to or is associated with: النظارة = the glasses

Even though إطار has no الـ, the whole phrase إطار النظارة is definite because the second noun is definite.

So إطار النظارة means the frame of the glasses, not just a frame of glasses.

In إطار النظارة, the word النظارة is the second term of the iḍāfa.

That means it is grammatically in the genitive case. In full vocalization, that is why it appears as:

• النظارةِ

So the fully vocalized phrase is:

• إِطارُ النَّظَّارَةِ

Case endings are often not written in ordinary Arabic text, but they are still part of the grammar.

نظيف is the predicate of the sentence, called خبر in Arabic grammar.

The sentence has two main parts:

• إطار النظارة = the subject/topic
• نظيف = the comment/predicate: clean

So the structure is:

• [subject] + [predicate]
• إطار النظارة + نظيف

That is why the sentence means:

• The frame of the glasses is clean.

Because here نظيف is a predicate, not an adjective modifying the noun directly.

Compare:

1. إطار النظارة نظيفٌ = The frame of the glasses is clean.

2. إطارُ النظارةِ النظيفُ = the clean frame of the glasses

In sentence 1, نظيف is telling you something about the frame, so it is the predicate and is normally indefinite.

In sentence 2, النظيف is an adjective attached directly to إطار, so it must match it in definiteness.

This is a very important distinction in Arabic.

نظيف agrees with إطار, not with النظارة.

The head noun of the phrase is إطار = frame, and إطار is masculine singular.

So the predicate must also be masculine singular:

• إطار النظارة نظيف.

If the main noun were feminine, then the predicate would be feminine too.

For example:

• النظارة نظيفة. = The glasses are clean.

Here نظيفة is feminine because النظارة is feminine.

In Modern Standard Arabic, نظارة often refers to eyeglasses / spectacles, even though English uses a plural word glasses.

So learners often find this surprising:

• Arabic may use a form that looks singular or feminine singular
• English often uses a plural translation: glasses

That is normal. Languages do not always divide things the same way.

So in this sentence:

• إطار النظارة is best understood as the eyeglass frame or the frame of the glasses

They talk about different things:

• إطار النظارة نظيف = The frame of the glasses is clean
• النظارة نظيفة = The glasses are clean

In the first sentence, only the frame is being described as clean.

In the second sentence, the whole pair of glasses is being described as clean.

This is a useful distinction, because Arabic often names the exact part being discussed.

Partly yes, partly no.

The noun phrase إطار النظارة is built in a way that often feels reversed compared with English:

• Arabic: frame the-glasses
• English: the frame of the glasses / the glasses frame

Then the predicate comes after it:

• إطار النظارة نظيف
• The frame of the glasses is clean

So the overall sentence pattern is not hard to follow, but the iḍāfa phrase is something English speakers usually need to get used to.

Yes. That is a very natural English translation.

Depending on context, these are all reasonable:

• The frame of the glasses is clean.
• The eyeglass frame is clean.
• The glasses frame is clean.

The most natural English version is usually:

• The eyeglass frame is clean.

These ideas are expressed differently in Arabic.

• A glasses frame is clean
  would normally begin with an indefinite noun phrase, something like:
  إطارُ نظارةٍ نظيفٌ
  = A glasses frame is clean

• The clean glasses frame
  would be a noun phrase, not a full sentence:
  إطارُ النظارةِ النظيفُ

So compare:

• إطارُ النظارةِ نظيفٌ
  = The eyeglass frame is clean
  full sentence

• إطارُ النظارةِ النظيفُ
  = the clean eyeglass frame
  noun phrase only

This difference between predicate and adjective is one of the most important things to notice in a sentence like this.