Szew jest dobry.

• szew = seam, stitch, or sometimes suture depending on context
• jest = is
• dobry = good

So the sentence structure is literally Seam is good / The seam is good.

Polish does not have articles like English a or the.
So szew can mean:

• a seam
• the seam

You understand which one is meant from context.

Because szew is a masculine singular noun, and adjectives in Polish must agree with the noun in:

• gender
• number
• sometimes also case

The adjective dobry is the masculine singular form.

Compare:

• dobry szew = a good seam
• dobra książka = a good book
• dobre okno = a good window

Szew is masculine.

A very common clue is that many masculine nouns in the dictionary form end in a consonant, as szew does. This is not the only pattern in Polish, but it is a very common one.

Because szew is masculine, the predicate adjective is dobry.

It is in the nominative case, because it is the subject of the sentence.

In Szew jest dobry:

• szew = subject, so nominative
• dobry agrees with it

This is the basic dictionary form of both words:

• szew
• dobry

In the present tense, Polish usually does include jest in a normal sentence like this:

• Szew jest dobry. = The seam is good.

You generally should not drop jest here in standard Polish.

This is different from some other Slavic languages where the present-tense to be is often omitted.

A rough pronunciation guide:

• sz sounds like English sh in shop
• e is like e in met
• w in Polish sounds like English v

So szew is pronounced roughly like shev.

The most neutral word order is:

• Szew jest dobry.

Polish word order is more flexible than English, so you can change it for emphasis, but the neutral, ordinary version is the one above.

For example:

• Szew jest dobry. = neutral statement
• Dobry jest szew. = marked or emphatic, something like It is the seam that is good

So for a learner, Szew jest dobry is the best default.

Because here dobry is not directly describing the noun inside a noun phrase like a good seam. It is part of the predicate after jest.

Compare:

• dobry szew = a good seam
• Szew jest dobry. = The seam is good.

So:

• before the noun: adjective inside the noun phrase
• after jest: predicate adjective

Both are normal, but they are used in different sentence structures.

Yes. Depending on context, szew can mean:

• seam in clothing or fabric
• stitch
• suture in medical contexts

So Szew jest dobry could mean things like:

• The seam is good
• The stitch is good
• The suture is good

The exact meaning depends on the situation.

You add nie before jest:

• Szew nie jest dobry. = The seam is not good.

This is the normal way to negate to be in Polish.