Δεν πλησιάζω τον βράχο όταν έχει πολλά κύματα, γιατί φοβάμαι να πέσω.

Greek often leaves out subject pronouns when they are clear from the verb ending.

So πλησιάζω by itself already means I approach / I go near. The ending -ω tells you it is first person singular.

You could add εγώ if you want emphasis or contrast:

Εγώ δεν πλησιάζω τον βράχο...
= I don’t go near the rock...

But in a normal sentence, Greek usually omits it.

Δεν is the normal negation used with indicative verbs, so it is the correct word for I do not approach / I don’t go near.

• Δεν πλησιάζω = I don’t approach
• Μην πλησιάζεις = Don’t approach

So δεν is for statements, while μη(ν) is used mainly for commands, subjunctive structures, and some other non-indicative uses.

Because βράχο is the direct object of πλησιάζω, it must be in the accusative case.

The dictionary form is:

• ο βράχος = the rock

But after a verb like πλησιάζω you need the accusative:

• τον βράχο = the rock

So:

• Ο βράχος είναι μεγάλος. = The rock is big.
• Πλησιάζω τον βράχο. = I approach the rock.

The article changes too:

• nominative: ο
• accusative: τον

Πλησιάζω means approach, go near, or come close to.

In this sentence, a natural English translation is often I don’t go near the rock rather than the more literal I don’t approach the rock.

So the Greek verb is a little broader than one very fixed English equivalent. Depending on context, it can mean:

• approach
• go near
• move closer to

This is a very natural question, because literally it looks like when it has many waves.

In Greek, έχει can sometimes be used in a more impersonal way, especially in everyday speech, to mean something like there are or to refer to conditions.

So here:

• όταν έχει πολλά κύματα = when there are many waves / when the sea is rough

The idea is understood from context: the sea has many waves, or the situation is wavy/rough.

A more explicit version could be:

• όταν η θάλασσα έχει πολλά κύματα = when the sea has many waves

But the shorter version is completely normal.

Because κύματα is a neuter plural noun, and the adjective must agree with it.

The singular and plural are:

• το κύμα = the wave
• τα κύματα = the waves

So the adjective πολύς / πολλή / πολύ changes to match:

• masculine plural: πολλοί
• feminine plural: πολλές
• neuter plural: πολλά

That is why we get:

• πολλά κύματα = many waves

The Greek present tense is often used for habitual or general actions, just like in English.

So Δεν πλησιάζω τον βράχο όταν έχει πολλά κύματα means something like:

• I don’t go near the rock when there are many waves.
• I never approach the rock when the sea is rough.

It describes what the speaker generally does in that situation, not only what is happening right now.

In Modern Greek, after many verbs, what English expresses with an infinitive is often expressed with να + verb.

English says:

• I am afraid to fall

Greek says:

• φοβάμαι να πέσω

There is no ordinary infinitive in Modern Greek like English to fall, so να is the normal way to introduce this kind of idea.

Here, να πέσω is the natural equivalent of to fall.

Because after να, Greek often uses the subjunctive, and here the verb appears in its aorist subjunctive form:

• basic verb: πέφτω = I fall / I am falling
• subjunctive form here: να πέσω = to fall / that I fall

The aorist form is used because the speaker is afraid of one complete event happening: falling.

So:

• φοβάμαι να πέσω = I’m afraid of falling / I’m afraid I might fall

If you used a present-type form such as να πέφτω, it would suggest something more repeated or ongoing, which is not the normal meaning here.

They are close, but not exactly identical.

• φοβάμαι να πέσω = I’m afraid to fall / I’m afraid of falling
• φοβάμαι μήπως πέσω = I’m afraid that I might fall

The second version with μήπως can sound a bit more like fear that something may happen. The version in your sentence, φοβάμαι να πέσω, is very natural and common.

So both are possible in Greek, but the sentence you have is perfectly normal.

Yes, επειδή could also work.

• γιατί = because
• επειδή = because / since

In everyday Greek, γιατί is extremely common and natural. Επειδή can sound a little more formal or a little more explicitly explanatory in some contexts.

So:

• ...γιατί φοβάμαι να πέσω.
• ...επειδή φοβάμαι να πέσω.

Both are correct here.

Yes. Greek word order is fairly flexible.

The given sentence is very natural:

Δεν πλησιάζω τον βράχο όταν έχει πολλά κύματα, γιατί φοβάμαι να πέσω.

But you could also rearrange parts for emphasis, for example:

Γιατί φοβάμαι να πέσω, δεν πλησιάζω τον βράχο όταν έχει πολλά κύματα.

That is grammatically possible, but the original order is more neutral and more likely in ordinary speech.

So the sentence first states the action, then gives the reason. That is the most straightforward pattern.