Peisajul este luminos.

Because Romanian usually puts the definite article at the end of the noun.

• peisaj = landscape / a landscape
• peisajul = the landscape

So -ul is the ending that means the here.

This is very common in Romanian:

• băiat = boy
• băiatul = the boy

Peisaj is a neuter noun.

In Romanian, neuter nouns behave:

• like masculine in the singular
• like feminine in the plural

So in this sentence, which is singular, peisajul takes the same kind of forms that a masculine singular noun would take. That is why the adjective is luminos, not a feminine form.

Este means is.

It is the 3rd person singular form of the verb a fi = to be.

So:

• eu sunt = I am
• tu ești = you are
• el/ea este = he/she/it is

In Peisajul este luminos, este links the subject (peisajul) to the adjective (luminos), just like is in English.

Because Romanian does not need a pronoun when the subject noun is already there.

English often says:

• The landscape is bright

Romanian does the same:

• Peisajul este luminos

There is no need to add a separate it, because peisajul is already the subject.

Because adjectives in Romanian agree with the noun in gender and number.

Here, peisajul is:

• singular
• neuter, but behaving like masculine in the singular

So the adjective takes the masculine singular form:

• luminos

Compare:

• peisajul luminos = the bright landscape
• camera luminoasă = the bright room

So if the noun were feminine singular, the adjective would usually change form.

Because here luminos is a predicate adjective: it describes the subject through the verb este.

Structure:

• Peisajul = subject
• este = is
• luminos = bright

This is the same basic pattern as English: The landscape is bright.

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

• peisajul luminos = the bright landscape

So:

• Peisajul este luminos. = The landscape is bright.
• Peisajul luminos... = The bright landscape...

Usually, Romanian adjectives most commonly come after the noun:

• peisaj luminos

Putting the adjective before the noun is possible in some contexts, but it often sounds more literary, emphatic, or less neutral.

For a beginner, the safest normal pattern is:

• peisaj luminos = a bright landscape
• peisajul este luminos = the landscape is bright

A simple English-friendly approximation is:

pey-SAH-zhul YES-te loo-mee-NOS

A few helpful details:

• pei sounds roughly like pay
• j in peisajul sounds like the s in measure
• este is commonly pronounced YES-te
• luminos has stress on the last syllable: -nos

A more IPA-style pronunciation would be approximately:

[pejˈsa.ʒul ˈjes.te lumiˈnos]

In normal standard Romanian, no: you should keep este here.

So the correct full sentence is:

• Peisajul este luminos.

Leaving it out would sound incomplete in ordinary standard usage.

As a learner, it is best to always include este in sentences like this.

To make it negative, put nu before the verb:

• Peisajul nu este luminos. = The landscape is not bright.

To make it a question, you can often keep the same word order and use question intonation:

• Peisajul este luminos? = Is the landscape bright?

You can also invert for a more explicit question:

• Este peisajul luminos?

Both are understandable.

Only if you mean the landscape.

Compare:

• peisajul = the landscape
• un peisaj = a landscape

So:

• Peisajul este luminos. = The landscape is bright.
• Un peisaj este luminos. = A landscape is bright.

You would not normally say Peisaj este luminos in standard Romanian for this meaning. Romanian usually wants either:

• a definite noun: peisajul
• or an indefinite noun: un peisaj

The plural of peisaj is peisaje.

So:

• Peisajele sunt luminoase. = The landscapes are bright.

Notice that several things change:

• peisajul → peisajele
• este → sunt
• luminos → luminoase

This happens because the noun is now plural, and the adjective must agree with it.