Η υπόθεση είναι κλειστή.

Because υπόθεση is a feminine noun in Greek.

Greek nouns have grammatical gender, so the article and adjective must match the noun:

• ο = masculine
• η = feminine
• το = neuter

Since υπόθεση is feminine, you get:

• η υπόθεση
• κλειστή (feminine form of closed)

So the whole sentence shows gender agreement.

Because it agrees with υπόθεση, which is feminine singular.

The adjective κλειστός changes form depending on gender:

• masculine: κλειστός
• feminine: κλειστή
• neuter: κλειστό

So here:

• η υπόθεση = feminine singular
• therefore κλειστή = feminine singular adjective

This is very common in Greek: adjectives must agree with the noun in gender, number, and case.

Είναι is the verb to be in the 3rd person singular of είμαι.

So it corresponds to is in English.

In this sentence:

• η υπόθεση = the subject
• είναι = is
• κλειστή = closed

So structurally it is:

The case / matter + is + closed

In standard Greek, not normally in this kind of sentence.

Unlike some languages, Greek usually keeps the present-tense form of to be in sentences like this:

• Η υπόθεση είναι κλειστή.

Leaving out είναι would sound incomplete or non-standard in ordinary usage.

Yes. This is an important distinction:

• η = the feminine singular article
• ή = or

The article η is unstressed, so it has no accent.

Examples:

• η υπόθεση = the case / the matter
• καφές ή τσάι = coffee or tea

So in your sentence, Η is simply the feminine article the.

It is in the nominative case, because it is the subject of the sentence.

Greek uses cases to show grammatical function. Here:

• η υπόθεση = subject, so nominative
• κλειστή also appears in nominative because it describes the subject after είναι

This is similar to how predicate adjectives work in many languages: the adjective matches the subject.

No. It can be used both literally and figuratively, depending on context.

Literally:

• a door can be κλειστή = closed

Figuratively:

• a case, issue, or matter can be κλειστή = closed, settled, no longer active

So in this sentence, the meaning is figurative, not necessarily about something physically shut.

Not always. Υπόθεση is a flexible word, and its meaning depends on context.

It can mean things like:

• case
• matter
• affair
• assumption / hypothesis

In this sentence, the surrounding context tells you which meaning is intended. So learners should remember that υπόθεση is broader than just one English word.

Yes. Greek word order is more flexible than English, though the neutral order here is:

• Η υπόθεση είναι κλειστή.

You could also hear:

• Κλειστή είναι η υπόθεση.

That changes the emphasis, putting more focus on closed.

So:

• standard, neutral statement: Η υπόθεση είναι κλειστή
• more emphasis on the adjective: Κλειστή είναι η υπόθεση

A simple pronunciation guide is:

ee ypóthesi íne kleestí

More approximately:

• Η = ee
• υπόθεση = ee-PO-the-see or more accurately y-PO-the-si, depending on how detailed you want to be
• είναι = EE-ne
• κλειστή = klee-STEE

The stressed syllables are:

• υπόθεση
• είναι
• κλειστή

So the rhythm is:

i i-PO-the-si I-ne kli-STI

Greek uses an accent mark to show which syllable is stressed.

In this sentence:

• υπόθεση → stress on πό
• είναι → stress on εί
• κλειστή → stress on the last syllable

This is very important in Greek pronunciation, because stress is part of the standard spelling.

Yes, but that would slightly change the structure and sometimes the nuance.

For example:

• Η υπόθεση έκλεισε.

This means something like the case closed / was concluded.

Compare:

• Η υπόθεση είναι κλειστή.
  Focus: the current state is closed

• Η υπόθεση έκλεισε.
  Focus: the event of closing happened

So the original sentence describes a state, while a verb like έκλεισε describes an action or result.

In this sentence, it functions as an adjective.

Historically and semantically, words like κλειστός / κλειστή / κλειστό are closely related to the idea of closed, but in ordinary grammar here you should treat κλειστή as an adjective agreeing with the noun.

So for learning purposes:

• υπόθεση = noun
• είναι = verb
• κλειστή = adjective

Yes. Depending on context, it can sound quite final or definitive.

Because κλειστή suggests that the matter is finished, settled, or no longer open, the sentence may sound like:

• a formal announcement
• a firm conclusion
• a refusal to continue discussing something

So even though the grammar is simple, the tone can be strong depending on the situation.