Ovaj kaput je deblji od moje jakne.

Ovaj has to agree with kaput in gender, number, and case.

• kaput is masculine
• singular
• nominative, because it is the subject of the sentence

So the correct form is ovaj kaput.

Compare:

• ovaj kaput = this coat
• ova jakna = this jacket
• ovo pismo = this letter

Je is the 3rd person singular present form of biti, meaning to be.

So:

• Ovaj kaput = this coat
• je deblji = is thicker

In a normal full sentence like this, je is required.

Deblji is the comparative form of the adjective debeo or debeo/debeli, depending on how it is presented in learning materials.

It means thicker.

This is not a simple add--er pattern like in English. Croatian comparatives are often formed with stem changes, and debeo becomes deblji.

Here deblji is:

• masculine
• singular
• nominative

because it agrees with kaput.

After a comparative adjective like deblji, Croatian often uses od to mean than.

So:

• deblji od moje jakne = thicker than my jacket

A useful pattern is:

X je + comparative + od + genitive

For example:

• veći od kuće = bigger than the house
• stariji od mene = older than me

Because od requires the genitive case.

The basic form is:

• jakna = jacket

But after od, it changes to genitive singular:

• od jakne = than/from the jacket

So:

• moja jakna = my jacket
• od moje jakne = than my jacket

Because moja jakna is nominative, but after od the whole noun phrase has to go into the genitive.

That means both words change appropriately:

• moja jakna = my jacket
• moje jakne = of my jacket / than my jacket

Here moje agrees with jakne in:

• feminine gender
• singular number
• genitive case

Yes. In Croatian, predicate adjectives still agree with the noun they describe.

So deblji must match kaput:

• kaput is masculine singular
• therefore deblji is masculine singular

If the subject were feminine, you would get:

• Ova jakna je deblja...

If it were neuter:

• Ovo pismo je deblje...

It depends on context.

With clothing or objects, deblji usually means thicker. With people, it can mean fatter or heavier.

In Ovaj kaput je deblji od moje jakne, the meaning is clearly thicker, because we are talking about a coat and a jacket.

Yes, Croatian word order is more flexible than English word order, because case endings show grammatical relationships.

The most neutral version here is:

• Ovaj kaput je deblji od moje jakne.

But other orders may be possible for emphasis, such as putting stress on ovaj kaput or on deblji. A learner should usually stick with the neutral order unless there is a special reason to change it.

With a simple noun phrase like moje jakne, od + genitive is the safest and most standard choice.

So:

• deblji od moje jakne = correct and natural

Nego is especially common when what follows is a clause, for example:

• Ovaj kaput je deblji nego što sam očekivao.
• This coat is thicker than I expected.

So for this sentence, od moje jakne is the form you should learn first.

No. Croatian does not have articles like English the or a/an.

Instead, Croatian often relies on:

• context
• word order
• demonstratives such as ovaj = this

So ovaj kaput specifically means this coat, not the coat.