Η γλάστρα είναι εντελώς άδεια.

Word by word:

• Η = the
• γλάστρα = plant pot / flowerpot
• είναι = is
• εντελώς = completely / entirely
• άδεια = empty

So the structure is very close to English: The plant pot is completely empty.

Η is the definite article meaning the.

Here it is:

• feminine
• singular
• nominative

It matches γλάστρα, which is a feminine singular noun.

Greek articles change depending on:

• gender
• number
• case

So here η is used because γλάστρα is feminine singular and is the subject of the sentence.

In this sentence, you can tell from the article η and the adjective άδεια.

A lot of Greek nouns ending in -α are feminine, and γλάστρα is one of them.

You can see the agreement:

• η γλάστρα = feminine singular
• άδεια = feminine singular adjective

So even if you did not know the noun yet, the rest of the sentence gives you a clue.

Because adjectives in Greek must agree with the noun they describe.

Since γλάστρα is:

• feminine
• singular

the adjective must also be:

• feminine
• singular

So:

• masculine: άδειος
• feminine: άδεια
• neuter: άδειο

Examples:

• Ο κουβάς είναι άδειος. = The bucket is empty.
• Η γλάστρα είναι άδεια. = The plant pot is empty.
• Το κουτί είναι άδειο. = The box is empty.

Είναι is the verb to be, here meaning is.

It can mean:

• he/she/it is
• you are (formal or plural)
• they are

In Modern Greek, είναι is the same form for all of those.

Here it means is, because the subject is η γλάστρα.

Εντελώς is an adverb meaning completely, entirely, or totally.

It strengthens άδεια:

• Η γλάστρα είναι άδεια. = The plant pot is empty.
• Η γλάστρα είναι εντελώς άδεια. = The plant pot is completely empty.

So it does not describe the pot directly; it modifies the adjective άδεια.

No, not exactly.

• πολύ = very / a lot
• εντελώς = completely / entirely

With empty, Greek strongly prefers εντελώς άδεια or simply άδεια.

Πολύ άδεια is possible in some contexts, but it sounds less natural if you literally mean completely empty.
So for this sentence, εντελώς is the better choice.

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

Η γλάστρα είναι εντελώς άδεια.

You may also hear:

• Η γλάστρα είναι άδεια εντελώς.
• Εντελώς άδεια είναι η γλάστρα.

But these usually sound more marked, emphatic, or context-dependent.

For a learner, the safest default is: subject + είναι + adverb + adjective

Not always.

In this sentence, η is used because we are talking about a specific pot: the pot.

If you wanted a more general or indefinite meaning, you might say:

• Μια γλάστρα είναι άδεια. = A plant pot is empty.
• Γλάστρες είναι άδειες. = Plant pots are empty. / The pots are empty, depending on context.

Greek often uses the definite article a lot, but whether you include it depends on whether the noun is specific or general.

A rough pronunciation is:

ee GLA-stra EE-ne en-de-LOHS A-thya

A few notes:

• γλ in γλάστρα starts with a sound like gl in glad
• είναι is pronounced roughly EE-ne
• εντελώς has the stress on the last syllable: -λώς
• άδεια is pronounced roughly A-thya or A-dhya, depending on accent and speaker

The stress marks matter:

• γλάστρα
• εντελώς
• άδεια

Greek pronunciation is very stress-sensitive, so it helps to notice where the accent is written.

Because άδεια can be more than one word in Greek.

It can be:

1. the feminine form of the adjective άδειος = empty
2. a noun meaning permission, license, or leave

For example:

• Η γλάστρα είναι άδεια. = The plant pot is empty.
• Έχω άδεια. = I have permission / I am on leave.

In your sentence, it is clearly the adjective meaning empty, because it agrees with γλάστρα and comes after είναι.

Usually γλάστρα means the pot / flowerpot / plant pot itself.

In everyday speech, though, people can sometimes use it loosely when talking about a potted plant as a whole, depending on context.

In this sentence, because it says είναι εντελώς άδεια, the meaning is clearly that the pot has nothing in it.

You need to change the article, noun, and adjective to plural:

• Η γλάστρα είναι εντελώς άδεια. = The plant pot is completely empty.
• Οι γλάστρες είναι εντελώς άδειες. = The plant pots are completely empty.

Notice the changes:

• η → οι
• γλάστρα → γλάστρες
• άδεια → άδειες

είναι stays the same.

Just add δεν before είναι:

Η γλάστρα δεν είναι εντελώς άδεια.
= The plant pot is not completely empty.

This is a very common pattern in Greek:

• είναι = is
• δεν είναι = is not

So δεν is the standard negation word for verbs in sentences like this.