Learn Hardcore Croatian: On je vrlo ljubazan.

You must use je, because Croatian normally uses the verb biti (to be) in the present tense, unlike Russian (which often drops it) or some other Slavic languages.

Correct: On je vrlo ljubazan. – He is very kind.
Incorrect: On vrlo ljubazan. ✗

So je is obligatory here in standard Croatian.

Can I leave out On and just say Je vrlo ljubazan?

No, you cannot start the sentence with je, and you normally would not drop on in this particular short sentence.

Two key points:

Clitic position:
- je is a clitic and cannot stand at the beginning of a sentence.
- It usually comes in the second position in the sentence (after the first stressed word or phrase).
Subject pronoun dropping:
- Croatian is a “pro‑drop” language; you can often omit subject pronouns when they’re clear from context:
  - Vrlo je ljubazan. – (He) is very kind.
- Here the subject he is understood from je and context.

So you can say:

On je vrlo ljubazan. – neutral, explicit
Vrlo je ljubazan. – often used when he is already clear from context

But Je vrlo ljubazan is wrong.

Why is it ljubazan and not ljubazno or ljubazna?

Because adjectives in Croatian agree with the gender, number, and case of the noun (or pronoun) they describe:

The subject on is masculine singular, in nominative.
So the adjective must also be masculine singular nominative: ljubazan.

Compare:

On je vrlo ljubazan. – He is very kind. (masculine)
Ona je vrlo ljubazna. – She is very kind. (feminine)
Ono je vrlo ljubazno. – It is very kind. (neuter, rarely used with this adjective)

Ljubazno here would be neuter singular, which doesn’t match on.

How would the sentence change if I talk about a woman instead of a man?

You change the pronoun and the adjective ending to match feminine gender:

Ona je vrlo ljubazna. – She is very kind/polite.

Breakdown:

ona – she (feminine)
ljubazna – feminine singular form of ljubazan

The verb je and vrlo stay the same.

What’s the difference between vrlo, jako, veoma, and puno? They all seem to mean “very”.

All four can intensify an adjective, but they differ slightly in usage and style:

vrlo – standard, neutral, maybe a bit more formal or written; good for most contexts.
- On je vrlo ljubazan.
jako – very common in everyday speech; can sound more colloquial or emotional.
- On je jako ljubazan.
veoma – similar to vrlo, often a bit formal or literary.
- On je veoma ljubazan.
puno – literally “a lot / much”; used a lot in speech, slightly more informal; often with verbs, but also with adjectives.
- On je puno ljubazan. (understandable, but less standard than vrlo/jako)

For a learner, vrlo and jako are the safest and most common choices.

Can I change the word order, for example say On je ljubazan vrlo?

In practice, you would not say On je ljubazan vrlo. The natural positions are:

On je vrlo ljubazan. – neutral, most natural
On je jako ljubazan. – replacing vrlo with jako is fine
On je stvarno vrlo ljubazan. – adding another adverb is also fine

Putting vrlo after the adjective (On je ljubazan vrlo) sounds unnatural or poetic at best and is not normal everyday Croatian.

So keep vrlo directly before the adjective: vrlo ljubazan.

What exactly does ljubazan mean – is it “kind”, “nice”, or “polite”?

Ljubazan combines the ideas of kind, polite, and courteous in interaction with people. It usually suggests:

He behaves nicely towards others.
He is polite and considerate.
He speaks and acts in a pleasant, respectful way.

Depending on context, you might translate it as:

He is very kind.
He is very polite.
He is very nice (to people).

If you want strictly “polite” in the sense of good manners, you can also use pristojan.

How do you pronounce ljubazan and the lj sound?

Pronunciation tips:

lj – a palatal sound, similar to the lli in English million or familiar.
ljubazan – roughly: LYOO-bah-zan

Syllables: lju‑ba‑zan
Stress is usually on the first syllable: LJU‑ba‑zan.

So: On je vrlo ljubazan ≈ “On yeh VR-lo LYOO-ba-zan”.

Why is je in the second position? Is that a rule?

Yes, Croatian has a well-known second position clitic rule. Short unstressed words like:

je, sam, si, smo, ste, su (forms of biti)
se, mi, ti, mu, joj, ga, ju, etc.

tend to appear in the second position of a clause. In On je vrlo ljubazan:

On – first word (stressed)
je – clitic in second position
vrlo ljubazan – the rest of the sentence

If you start with an adverb, the clitic still goes second:

Vrlo je ljubazan. – Very kind is he.

This second-position rule is strong in standard Croatian.

How do I make this sentence negative?

You add nije (the negative form of je) instead of je:

On nije vrlo ljubazan. – He is not very kind.

Common nuance options:

On nije baš ljubazan. – He’s not really kind.
On nije nimalo ljubazan. – He’s not kind at all.

But structurally, you just replace je with nije:

On je vrlo ljubazan.
On nije vrlo ljubazan.

What are the other present tense forms of biti (to be), like je?

The present tense of biti (to be) in standard Croatian is:

ja sam – I am
ti si – you are (singular, informal)
on/ona/ono je – he/she/it is
mi smo – we are
vi ste – you are (plural or polite singular)
oni/one/ona su – they are (masc./fem./neut.)

So you could say:

Ja sam vrlo ljubazan. – I am very kind. (male speaker)
Mi smo vrlo ljubazni. – We are very kind. (group including at least one man)

How does ljubazan change in the plural if I say “They are very kind”?

Adjectives agree with the subject in gender and number. For They are very kind:

Oni su vrlo ljubazni. – They are very kind. (group with at least one male)
One su vrlo ljubazne. – They are very kind. (all female group)
Ona su vrlo ljubazna. – They are very kind. (neuter plural, usually objects)

So:

singular masculine: ljubazan – On je vrlo ljubazan.
plural masculine (mixed or all male): ljubazni – Oni su vrlo ljubazni.
plural feminine: ljubazne – One su vrlo ljubazne.