Jedwab jest delikatny.

In this sentence, jest is the 3rd person singular form of być (to be), so it means is.

In standard Polish, you normally keep jest in a sentence like this:

• Jedwab jest delikatny.

Leaving it out would sound unnatural in ordinary modern Polish. Polish sometimes omits forms of to be in certain styles or expressions, but not usually in a basic sentence like this one.

Jedwab is a masculine noun in Polish, specifically masculine inanimate.

Because Polish adjectives must agree with the noun they describe, delikatny is also in the:

• masculine
• singular
• nominative

form.

That is why you get:

• jedwab → masculine singular
• delikatny → masculine singular

If the noun were feminine, you would use delikatna.
If it were neuter, you would use delikatne.

It is in the nominative case.

That is because jedwab is the subject of the sentence:

• Jedwab jest delikatny.

In simple statements like X is Y, the subject is usually nominative.

Also, the adjective delikatny matches that nominative masculine singular form.

Yes, delikatny is an adjective.

It often corresponds to English delicate, but like many words, its exact sense depends on context. It can mean things like:

• physically delicate
• gentle
• subtle
• mild

In Jedwab jest delikatny, it most naturally refers to silk being soft/fine/delicate in texture.

A simple learner-friendly approximation is:

• Jedwab ≈ YED-vap
• jest ≈ yest
• delikatny ≈ deh-lee-KAT-nih

A few helpful pronunciation notes:

• j in Polish sounds like English y in yes
• w sounds like English v
• final b in jedwab is pronounced more like p at the end of the word, which is why YED-vap is a useful approximation
• stress in Polish is usually on the second-to-last syllable, so:
  • jedwab
  • jest
  • delikatny

Yes, Polish word order is fairly flexible, but the neutral, most natural order here is:

• Jedwab jest delikatny.

You might also hear or see:

• Delikatny jest jedwab.

But that sounds more marked or emphatic, as if contrasting silk with something else.

So for normal everyday use, stick with:

• Jedwab jest delikatny.

No, that would not work well.

The particle to is often used when identifying something as a noun phrase, for example:

• Jedwab to materiał.
  (Silk is a material.)

But with an adjective like delikatny, you normally use jest:

• Jedwab jest delikatny.

So:

• X to Y works well when Y is a noun
• X jest Y works well when Y is an adjective

Not with jedwab, because jedwab is masculine.

You would use:

• delikatny for masculine singular
• delikatna for feminine singular
• delikatne for neuter singular
• delikatne/delikatni/delikatne for plural, depending on the noun type and grammar context

For example:

• Tkanina jest delikatna. — feminine
• Włókno jest delikatne. — neuter
• Jedwab jest delikatny. — masculine

So the adjective form must match the noun.

Here it is being used as a material noun, similar to English silk.

So jedwab here means the substance/material, not a single item.

That is why the sentence feels like:

• Silk is delicate

rather than:

• A silk is delicate

Polish often uses singular nouns this way when talking about materials or substances.

Polish does not have articles like English a/an/the.

So:

• Jedwab jest delikatny.

can mean something like:

• Silk is delicate
• The silk is delicate

depending on context.

You figure out the intended meaning from the situation, not from an article.

It is a complete and natural Polish sentence.

It is also simple and textbook-like, but not unnatural. A Polish speaker could absolutely say it.

It has a very standard structure:

• noun + jest + adjective

So it is a good model sentence for beginners.

The dictionary forms are:

• jedwab — noun
• być — verb (jest is one form of it)
• delikatny — adjective

So in dictionary-style form, the sentence is built from:

• jedwab
• być
• delikatny

This is useful because Polish words often change form depending on grammar, but dictionaries usually list the base form.