Это великий писатель.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Это великий писатель = This is a great writer
• literally: This great writer

Russian understands the is automatically here.

You do see forms of to be in other tenses:

• Это был великий писатель = This was a great writer
• Это будет великий писатель = This will be a great writer

So the missing is is completely normal.

Here это means something like this, that, or this is depending on context.

In this sentence, это is commonly used to identify someone or something:

• Это великий писатель = This is a great writer

A very important point: in this kind of sentence, это does not change for gender.

So even though писатель is masculine, you still say:

• Это писатель
• Это студент
• Это женщина
• Это книга

So это does not have to match писатель in gender here.

Because писатель is a masculine singular noun, and adjectives must agree with the noun they describe.

So:

• masculine singular: великий писатель
• feminine singular: великая книга
• neuter singular: великое произведение
• plural: великие писатели

Since писатель is masculine singular, the correct form is великий.

A lot of Russian masculine nouns end in a consonant, and писатель fits that pattern.

So:

• писатель = masculine
• therefore: великий писатель

Also, many nouns referring to male people are masculine by default.

Be careful, though: писатель can sometimes be used more generally as writer, but grammatically it is still a masculine noun.

They are in the nominative case.

• великий = nominative masculine singular
• писатель = nominative singular

This is the basic dictionary form of both words.

In a simple identification sentence like this, the noun phrase великий писатель stays in the nominative.

Russian has no articles.

So писатель can mean:

• a writer
• the writer

The exact meaning depends on context.

So Это великий писатель could be understood as:

• This is a great writer
• sometimes, in the right context, This is the great writer

Usually, without special context, English would most naturally translate it as This is a great writer.

They are different.

• великий means great in the sense of important, outstanding, historically significant
• большой usually means big, large

So:

• великий писатель = a great writer
• большой писатель is not the normal way to say that and could sound odd or mean something else depending on context

For famous cultural or historical figures, Russian often uses великий:

• великий поэт = a great poet
• великий композитор = a great composer

Yes, but it means something slightly different.

• Это великий писатель = This is a great writer / That is a great writer
  This is often used when identifying someone.
• Он великий писатель = He is a great writer
  This is used when you are already talking about him.

So the difference is not mainly grammar, but what role the sentence plays in the conversation.

The order Это великий писатель is the most neutral and natural here.

Russian word order is more flexible than English, but changing it changes the emphasis.

For example:

• Это великий писатель = neutral
• Великий писатель — это ... = A great writer is ... / emphasis on the category
• Писатель великий = possible in special contexts, but not the normal neutral order

Also, adjectives usually come before the noun in standard Russian:

• великий писатель not normally
• писатель великий

A rough pronunciation guide:

• Это ≈ EH-tuh
• великий ≈ vye-LEE-kee(y)
• писатель ≈ PEE-suh-tyel’

The stress is:

• э́то
• вели́кий
• пи́сатель

A few pronunciation notes:

• The final -ий in великий is pronounced like a soft -iy
• The ь in писатель is a soft sign; it does not make a separate sound, but it softens the л

Not normally.

Это великий писатель most naturally means:

• This is a great writer

If you want to say This writer is great, Russian would more naturally say:

• Этот писатель великий
• or more idiomatically depending on context, perhaps Этот писатель — великий

So in your sentence, это is working more like this is, not this writer.

Traditionally, писатель is the standard word for writer and is grammatically masculine.

There is also писательница, which specifically means female writer.

So you may see:

• великий писатель = a great writer / often masculine
• великая писательница = a great female writer

In modern usage, писатель can sometimes be used generically, but grammatically it still behaves as a masculine noun.

Good question. Russian often uses a dash in sentences where English uses is, especially in written style:

• Пушкин — великий поэт.

But with это, a dash is often not needed in a simple sentence like:

• Это великий писатель.

So this sentence is perfectly normal without a dash.

You may still see dashes in other sentence types for emphasis or in more formal writing, but here the version without a dash is standard and natural.