Μην τρυπάς τον τοίχο χωρίς να ρωτήσεις τον ιδιοκτήτη.

Because μην is the negative particle used for commands and the subjunctive.

• Μην τρυπάς... = Don’t drill...
• Δεν τρυπάς... would mean You are not drilling... or You don’t drill...

So for negative instructions like don’t do X, Greek uses μη(ν), not δεν.

That is very common in Modern Greek. After μην, Greek uses the subjunctive, but for many verbs the form looks identical to the ordinary non-past form.

So in:

• μην τρυπάς

the form τρυπάς is functioning as the verb in a negative command. You can think of it as:

• don’t be drilling / don’t drill

Even though it looks like the everyday you drill / you are drilling, the presence of μην changes its job in the sentence.

This is an aspect difference.

• μην τρυπάς = imperfective
  This sounds like a general prohibition or a warning about the action as an activity: don’t go drilling / don’t drill
• μην τρυπήσεις = perfective
  This focuses more on a single completed act: don’t drill / don’t make a hole

Both can be possible in different contexts, but μην τρυπάς τον τοίχο sounds very natural for a general instruction or house rule.

Χωρίς να means without doing... and often corresponds naturally to English without... or before...

So:

• χωρίς να ρωτήσεις τον ιδιοκτήτη
  = without asking the owner
  = before asking the owner

Literally, it is something like without to ask, but in normal English we translate it more naturally.

Again, this is about aspect.

After χωρίς να, Greek uses the subjunctive, and here ρωτήσεις is the perfective/aorist subjunctive form. It treats the asking as one complete action:

• χωρίς να ρωτήσεις = without asking first

If you said:

• χωρίς να ρωτάς

it would sound more like without asking habitually / without asking in general, which is less natural here. The sentence is talking about one specific thing you should do first: ask the owner.

In both places, τον is the masculine singular accusative definite article, meaning the.

• τον τοίχο = the wall
• τον ιδιοκτήτη = the owner

It is not a pronoun here, because each τον is immediately followed by a noun.

Because they are in the accusative case, not the dictionary form.

Dictionary forms are usually nominative:

• ο τοίχος = the wall
• ο ιδιοκτήτης = the owner

But as direct objects, they become accusative:

• τον τοίχο
• τον ιδιοκτήτη

So in this sentence:

• you drill the wall
• you ask the owner

Both nouns are receiving the action, so they appear in the accusative.

Literally, it means owner.

In a housing context, though, it often means the person who owns the property you are renting, so in English that may be translated as landlord.

So here:

• τον ιδιοκτήτη could be understood as the owner
• and in real-life apartment context, very often the landlord

Yes. The verb is τρυπάω or τρυπώ.

It means things like:

• to pierce
• to poke
• to drill
• to make a hole in

So τρυπάς is the you form of that verb. In this sentence it means drill / make a hole in.

Because τον is the normal masculine accusative singular article, and the final -ν is usually kept before certain sounds, including τ.

Since τοίχο begins with τ, τον τοίχο is the expected form.

Learners often notice that final -ν can disappear in some contexts, but here keeping it is normal and standard.

Yes, Greek word order is more flexible than English, but this version is the most neutral and natural:

• Μην τρυπάς τον τοίχο χωρίς να ρωτήσεις τον ιδιοκτήτη.

You could move parts around for emphasis, but the sentence as given is the straightforward way to say it. The structure is:

• Μην τρυπάς = don’t drill
• τον τοίχο = the wall
• χωρίς να ρωτήσεις τον ιδιοκτήτη = without asking the owner

Usually, no.

The phrase χωρίς να ρωτήσεις τον ιδιοκτήτη is closely connected to the main verb τρυπάς, so Greek normally writes it without a comma:

• Μην τρυπάς τον τοίχο χωρίς να ρωτήσεις τον ιδιοκτήτη.

A comma would usually feel unnecessary here.