Andrei este serios.

Este is the 3rd person singular form of the verb a fi, which means to be.

So in this sentence:

• Andrei = the subject
• este = is
• serios = an adjective describing Andrei

Romanian often uses este in full, especially in more careful or neutral speech. In everyday speech, people very often shorten it to e:

• Andrei este serios.
• Andrei e serios.

Both are correct.

Because serios agrees with Andrei, and Andrei is masculine singular.

Romanian adjectives change form depending on gender and number. For this adjective:

• masculine singular: serios
• feminine singular: serioasă
• masculine plural: serioși
• feminine plural: serioase

So:

• Andrei este serios.
• Maria este serioasă.
• Băieții sunt serioși.
• Fetele sunt serioase.

This is a very common feature of Romanian grammar.

The normal, neutral word order is:

Subject + este + adjective

So:

• Andrei este serios.

This is the most natural order for a simple statement.

Romanian can change word order for emphasis, but that is less neutral. For example, putting serios first would sound marked or contrastive in many contexts. A learner should stick with Andrei este serios unless there is a special reason to change it.

Yes. E is a very common short form of este.

So both of these are correct:

• Andrei este serios.
• Andrei e serios.

A useful rule:

• este = slightly more formal, careful, or written
• e = very common in everyday speech

Learners should understand both.

Because Andrei is a proper name, and Romanian normally does not use an article before a person’s name in a basic sentence like this.

So Romanian says:

• Andrei este serios.

not something like The Andrei is serious.

That is similar to English, where you also normally do not put the before a person’s name.

Here, serios is not directly attached to the noun inside a noun phrase. It is a predicate adjective, linked to the subject by este.

So the structure is:

• Andrei = subject
• este = linking verb
• serios = adjective describing the subject

This is like English Andrei is serious.

In Romanian, adjectives can appear after nouns when they directly modify them, but after a fi they function just like this:

• Andrei este serios.
• Maria este fericită.
• Copiii sunt obosiți.

A simple English-friendly guide:

• Andrei ≈ ahn-DRAY
• este ≈ YES-te
• serios ≈ seh-ree-OS

A few pronunciation notes:

• ei in Andrei sounds roughly like ay in day
• e at the start of este is pronounced clearly, not silent
• the final -os in serios is pronounced

If you want a rough full pronunciation: ahn-DRAY YES-te seh-ree-OS

Yes, Romanian often drops subject pronouns when the meaning is clear. Romanian is more flexible than English in this way.

With a name, you usually just say the name:

• Andrei este serios.

If you were using a pronoun, Romanian may or may not include it:

• El este serios. = He is serious
• Este serios. = He is serious, if the context makes it clear who he is

So Romanian often does not need an explicit pronoun, especially in context.

You add nu before the verb:

• Andrei nu este serios.
• Andrei nu e serios.

This means Andrei is not serious.

This is the normal Romanian pattern for negation with a fi:

• este → nu este
• e → nu e

A natural yes/no question is:

• Andrei este serios?
• Andrei e serios?

In everyday speech, Romanian often uses the same word order as the statement and relies on intonation.

You may also sometimes see more formal or emphatic question patterns, but for a beginner, the easiest rule is:

• statement: Andrei este serios.
• question: Andrei este serios?

Often yes, but context matters.

Serios can describe someone as:

• serious in personality
• not joking
• earnest
• thoughtful or responsible

So it can overlap well with English serious, but like many adjectives, the exact nuance depends on context.

For example, Andrei este serios could mean:

• he has a serious personality
• he is speaking seriously
• he is not fooling around

The sentence by itself does not tell you which nuance is intended.

If the subject becomes plural, both the verb and the adjective change.

For masculine or mixed plural:

• Andrei și Mihai sunt serioși.

For feminine plural:

• Maria și Elena sunt serioase.

Notice the changes:

• este → sunt
• serios → serioși or serioase

So Romanian shows agreement both in the verb and in the adjective.