Ο συνδρομητής δεν χρησιμοποιεί καρτοκινητή τηλεφωνία.

Ο is the masculine singular definite article, meaning the.

It is used because συνδρομητής is a specific noun phrase: ο συνδρομητής = the subscriber.

Grammatically, ο is:

• masculine
• singular
• nominative

It matches συνδρομητής, which is also masculine singular nominative.

Συνδρομητής is a masculine singular noun in the nominative case.

In this sentence, it is the subject, so the nominative is the expected case.

A rough breakdown:

• base meaning: someone with a subscription / subscriber
• ending -τής is a very common masculine noun ending in Greek

So:

• ο συνδρομητής = the subscriber

Δεν is the normal negation word used before indicative verbs. It means not.

So:

• χρησιμοποιεί = uses
• δεν χρησιμοποιεί = does not use

In Greek, δεν normally comes directly before the verb, which is exactly what happens here.

A useful contrast:

• δεν is used with ordinary statements
• μην is used in commands or after certain particles

So this sentence uses the correct negative form for a simple statement.

Χρησιμοποιεί is:

• present tense
• third person singular
• active voice

It comes from the verb χρησιμοποιώ, meaning to use.

So χρησιμοποιεί means:

• he uses
• she uses
• it uses

Here, because the subject is ο συνδρομητής, it means the subscriber uses or, with the negation, the subscriber does not use.

The present tense here expresses a general fact or habitual situation, much like the English simple present.

Greek does not need a helper verb like English do / does for negation.

English says:

• He does not use

Greek simply says:

• Δεν χρησιμοποιεί

So the negation is made by putting δεν before the main verb, without adding another verb.

It is a noun phrase made of:

• καρτοκινητή = an adjective
• τηλεφωνία = a noun

The adjective describes the noun, so together they mean something like prepaid mobile telephony / prepaid mobile service.

Both words are:

• feminine
• singular

So they agree with each other, which is a basic rule in Greek:

• adjectives agree with the nouns they describe in gender, number, and case

Because it modifies τηλεφωνία, and τηλεφωνία is a feminine noun.

In Greek, adjectives must match the noun they describe. Since τηλεφωνία is feminine singular, the adjective also appears in the feminine singular form:

• καρτοκινητή τηλεφωνία

If the noun were masculine or neuter, the adjective would change form too.

Greek often leaves out the article when speaking generally about a type of thing, service, or activity.

Here, καρτοκινητή τηλεφωνία is being used in a general sense:

• the subscriber does not use prepaid mobile service

So the article is not necessary.

If you added the article:

• την καρτοκινητή τηλεφωνία

the sentence could sound more specific, as if referring to a particular service or a more clearly identified kind of mobile plan.

So the version without the article sounds natural for a general statement.

It is the direct object of χρησιμοποιεί, so its grammatical role is accusative.

However, in this phrase, the accusative form looks the same as the nominative form. That is very common in Greek with many feminine singular nouns and adjectives.

So even though the form does not visibly change, its function in the sentence is still that of the object:

• subject: ο συνδρομητής
• verb: δεν χρησιμοποιεί
• object: καρτοκινητή τηλεφωνία

Yes, Greek word order is more flexible than English word order.

The neutral, straightforward order here is:

• subject + δεν + verb + object

So:

• Ο συνδρομητής δεν χρησιμοποιεί καρτοκινητή τηλεφωνία.

But Greek can move things around for emphasis. For example, the object could be fronted in some contexts. Still, for a learner, the version given is the most neutral and easiest pattern to follow.

One important point stays the same:

• δεν normally stays right before the verb

Normally it sounds like a general fact or habitual situation.

Because the verb is in the present tense, Greek often uses it the same way English uses the simple present:

• to describe habits
• routines
• general truths
• ongoing states

So the sentence is most naturally understood as:

• the subscriber does not use prepaid mobile service in general

If you wanted to focus on a single completed action, Greek would usually use a different verb form or a different tense/aspect.

Yes. In Greek, stress marks are important for correct pronunciation, and they are written in normal spelling.

For example:

• συνδρομητής
• χρησιμοποιεί
• καρτοκινητή
• τηλεφωνία

The accent shows which syllable is stressed. This matters both for pronunciation and for writing correctly.

For a learner, it is a good idea to memorize Greek words together with their written accent.