Ovaj elektronički potpis još vrijedi.

Because potpis is a masculine singular noun in the nominative case, and the demonstrative ovaj has to agree with it.

• ovaj = this, for masculine singular nouns
• ova = this, for feminine singular nouns
• ovo = this, for neuter singular nouns

So:

• ovaj potpis = this signature
• ova isprava = this document
• ovo pismo = this letter

For the same reason: it has to agree with potpis.

Elektronički is an adjective meaning electronic, and here it is in the masculine singular nominative form, because it describes potpis.

Compare:

• elektronički potpis = electronic signature
• elektronička poruka = electronic message
• elektroničko pismo = electronic letter / email

So both ovaj and elektronički are matching potpis.

Potpis is masculine.

A very common clue is that many masculine Croatian nouns in the dictionary form end in a consonant, and potpis does exactly that.

Its basic form is:

• potpis = signature

Because it is masculine, words that go with it also take masculine forms:

• ovaj potpis
• elektronički potpis

Here još means still.

So još vrijedi means is still valid.

Be careful, because još can also mean more / another / yet, depending on context. But in this sentence, the natural meaning is still.

Examples:

• Još čekam. = I’m still waiting.
• Želite li još kave? = Would you like more coffee?
• Još jedan primjer. = One more example.

Vrijedi is the 3rd person singular present tense of the verb vrijediti.

In this sentence, it means is valid / remains valid / is still in force.

This verb is often used for things like:

• tickets
• documents
• contracts
• passwords
• signatures
• offers

Examples:

• Karta vrijedi do petka. = The ticket is valid until Friday.
• Ponuda više ne vrijedi. = The offer is no longer valid.

A useful detail: vrijediti can also mean to be worth in other contexts.

• To vrijedi puno novca. = That is worth a lot of money.

So the exact meaning depends on context.

Because vrijedi is already a full verb. It does not need a separate verb like English is.

In English, we say is valid, using to be + adjective.
In Croatian, the idea is often expressed with a single verb:

• vrijedi = is valid / counts / remains in force

So the sentence is not built like X is valid with a hidden to be. Instead, vrijedi carries the core meaning by itself.

The given word order is the most natural and neutral:

Ovaj elektronički potpis još vrijedi.

Croatian word order is more flexible than English, but not every alternative sounds equally natural.

Why this order works well:

• Ovaj elektronički potpis introduces the subject clearly.
• još comes right before the verb and naturally modifies it.
• vrijedi stays at the end, which is very normal in Croatian statements.

You may also hear other orders for emphasis, for example:

• Još vrijedi ovaj elektronički potpis.

This is possible, but it sounds more marked, as if emphasizing it is still valid.

The most natural negative version is:

Ovaj elektronički potpis više ne vrijedi.

This means This electronic signature is no longer valid.

A very important contrast:

• još vrijedi = is still valid
• više ne vrijedi = is no longer valid

Do not confuse that with:

• još ne vrijedi = is not valid yet

So:

• još = still
• više ne = no longer
• još ne = not yet

Yes, you may hear both, but elektronički potpis is the standard and especially common formal/legal term in Croatian.

• elektronički potpis = the usual official term for electronic signature
• digitalni potpis = also understandable, but it can sometimes refer more specifically to digital signature in a technical sense

So if you are talking about the standard legal concept, elektronički potpis is the safer choice.

In standard Croatian, vrijediti is the most natural choice in a sentence like this.

• Ovaj elektronički potpis još vrijedi.

You may also encounter važiti in related meanings such as to apply or to be in force, but vrijediti is very common for things being valid.

For a learner of Croatian, vrijediti is the best verb to remember in this kind of sentence.

A rough pronunciation guide is:

OH-vai eh-lehk-TROH-neech-kee POHT-pees yosh VRYEH-dee

A few helpful pronunciation notes:

• j is pronounced like English y
• š is pronounced like sh
• č is pronounced roughly like ch
• vrijedi begins with a cluster that can feel tricky for English speakers; try saying vrye-
• stress in Croatian is not usually marked in normal writing, so it is best learned by listening

If you want to sound natural, pay special attention to:

• ovaj = oh-vai
• još = yosh
• vrijedi = vryeh-di