Θέλω μια ουσιαστική απάντηση, όχι μόνο ένα «ίσως».

Because απάντηση is a feminine noun in Greek.

That means the article and the adjective both have to agree with it in gender, number, and case:

• μια = feminine singular indefinite article
• ουσιαστική = feminine singular form of the adjective
• απάντηση = feminine singular noun

So the whole phrase matches grammatically.

Compare:

• μια ουσιαστική απάντηση = a substantial/meaningful answer
• ένα ουσιαστικό ερώτημα = a substantial/essential question

In the second example, ερώτημα is neuter, so the article and adjective become ένα ουσιαστικό.

Yes. Ουσιαστική comes from ουσία, which means essence or substance.

So ουσιαστική απάντηση literally suggests an answer with real substance. In natural English, depending on context, it could be translated as:

• a substantial answer
• a meaningful answer
• a real answer
• a substantive answer

It does not mean just any answer. It implies the speaker wants something serious, useful, or concrete, not something vague or evasive.

No. In Greek, θέλω simply means I want, and it can take a direct object directly, just like English:

• Θέλω καφέ. = I want coffee.
• Θέλω μια απάντηση. = I want an answer.

So:

• Θέλω μια ουσιαστική απάντηση = I want a substantial answer

There is no need for an extra verb like have.

It is in the accusative, because it is the direct object of Θέλω.

In Modern Greek, the accusative is used for the thing someone wants, sees, has, knows, etc.

Here:

• Θέλω = I want
• μια ουσιαστική απάντηση = the thing wanted

For many feminine nouns like απάντηση, the nominative and accusative singular look the same, so you do not see a visible change on the noun itself. But grammatically, it is accusative here.

Όχι μόνο means not only / not just.

In this sentence, it introduces a contrast:

• Θέλω μια ουσιαστική απάντηση, όχι μόνο ένα ίσως.
• Literally: I want a substantial answer, not only just a maybe.

In more natural English, you would usually say:

• I want a substantial answer, not just a maybe.

So Greek is using όχι μόνο to reject something insufficient. It emphasizes that ίσως is not enough.

You will also see όχι μόνο ... αλλά και ... = not only ... but also ..., but here the second half is omitted because the contrast is already clear from context.

Yes, ίσως is usually an adverb meaning maybe / perhaps.

But here it is being used like a noun, meaning something like:

• a maybe
• just a maybe
• an answer like maybe

Greek can do this, just as English can. When a word is used as a quoted expression or as a thing in itself, it can take an article:

• ένα ναι = a yes
• ένα όχι = a no
• ένα γιατί = a why
• ένα ίσως = a maybe

So ένα ίσως is perfectly natural as a way to refer to the word or type of response itself.

When Greek turns a word like ίσως into a noun-like expression, it often uses the neuter singular article by default.

So:

• ένα ίσως = a maybe
• ένα ναι = a yes
• ένα όχι = a no

This is very common with words, expressions, and abstract reply-types that are being treated as things.

So even though ίσως is not normally a noun, once it is used this way, ένα is the natural article.

Both μια and μία can mean a / one in feminine singular.

In modern everyday Greek:

• μια is the most common spelling in ordinary use
• μία is also correct, and may look slightly more careful, formal, or emphatic in some contexts

So:

• μια απάντηση
• μία απάντηση

Both are acceptable. In this sentence, μια is completely natural and standard.

Greek traditionally uses guillemets:

• « »

These are the standard quotation marks in Greek typography.

So:

• ένα «ίσως»

means the same as English:

• a “maybe”

The quotation marks show that the speaker is referring to the word itself, or to that exact kind of response, not just using the word normally in the sentence.

The comma is very natural here because the second part adds a clarifying contrast:

• Θέλω μια ουσιαστική απάντηση, όχι μόνο ένα «ίσως».

The comma helps separate:

1. what the speaker wants
2. what the speaker rejects as insufficient

In writing, this punctuation makes the sentence easier to read and gives it the right rhetorical pause. In speech, you would usually hear a small pause there too.

Yes. This sentence is natural, but Greek offers several alternatives depending on tone.

For example:

• Θέλω μια ξεκάθαρη απάντηση, όχι ένα απλό ίσως.
  = I want a clear answer, not a simple maybe.

• Θέλω κάτι πιο συγκεκριμένο από ένα ίσως.
  = I want something more specific than a maybe.

• Δεν μου αρκεί ένα ίσως· θέλω ουσιαστική απάντηση.
  = A maybe is not enough for me; I want a substantial answer.

Each version shifts the emphasis slightly:

• ουσιαστική = substantial, meaningful
• ξεκάθαρη = clear
• συγκεκριμένο = specific
• δεν μου αρκεί = is not enough for me

So the original sentence has a strong tone of wanting a serious, meaningful reply rather than a vague one.