Questo documento è falso.

Questo means this.

It is questo because it has to agree with documento, which is a masculine singular noun in Italian.

The main forms are:

• questo = masculine singular
• questa = feminine singular
• questi = masculine plural
• queste = feminine plural

So:

• questo documento = this document
• questa lettera = this letter

Because è is the verb is from essere.

The accent is important because:

• è = is
• e = and

So in this sentence, è falso means is false / is fake, not and false.

The accented è is also pronounced as an open e sound.

In Italian, a demonstrative like questo usually takes the place of the article.

So Italian says:

• questo documento = this document

not normally:

• questo il documento

Compare:

• il documento = the document
• questo documento = this document

This works much like English, where this already does the job and you do not say this the document.

Because adjectives in Italian agree with the noun they describe.

Here, documento is masculine singular, so the adjective is also masculine singular:

• documento falso

If the noun changed, the adjective would change too:

• questa firma è falsa = this signature is fake
• questi documenti sono falsi = these documents are fake
• queste prove sono false = this evidence / these proofs are false

After essere, the adjective still agrees with the subject.

It can cover several related ideas, depending on context.

With documento, falso often means:

• fake
• not genuine
• forged

So Questo documento è falso often sounds like This document is fake or This document is forged.

In other contexts, falso can also mean false in the sense of not true:

• Questo è falso = This is false

So the exact English translation depends on what kind of thing is being described.

Because in this sentence falso is not directly attached to the noun inside the noun phrase. It comes after è and works as a predicate adjective.

The structure is:

• Questo documento = subject
• è = is
• falso = predicate adjective

So the sentence literally follows the pattern:

• This document is fake

If you put the adjective directly with the noun, you get a different structure:

• un documento falso = a fake document

Both are correct, but they are built differently.

Yes, absolutely.

Both are correct, but the focus is slightly different:

• Questo documento è falso = This document is fake.
• Questo è un documento falso = This is a fake document.

The first starts from the document itself. The second starts from this and then identifies what it is.

In many situations, they are very close in meaning.

A careful pronunciation is approximately:

KWES-to do-ku-MEN-to eh FAL-so

IPA: [ˈkwɛsto dokuˈmento ɛ ˈfalso]

A few helpful points:

• qu in questo sounds like kw
• stress falls on -men- in documento
• è is pronounced like an open eh
• falso has stress on the first syllable: FAL-so

It can do both.

In your sentence, questo is followed by a noun:

• Questo documento = this document

But questo can also stand alone when the noun is understood:

• Questo è falso = This is false
• Questo è importante = This is important

So questo can be either:

• a demonstrative adjective: questo documento
• a demonstrative pronoun: questo

The plural is:

Questi documenti sono falsi.

That means These documents are fake / false.

Notice how everything changes to match the plural:

• questo → questi
• documento → documenti
• è → sono
• falso → falsi

This is a very common Italian pattern: demonstrative, noun, verb, and adjective all match correctly.