Дырка была не то чтобы большой, но без иголки и нитки её нельзя было аккуратно зашить.

Не то чтобы is a very common Russian expression meaning something like:

• not exactly
• not really
• it’s not that ...
• I wouldn’t quite say ...

So:

• Дырка была не то чтобы большой
  = The hole wasn’t exactly big / It wasn’t really big

It often softens what you are saying. Instead of directly saying the hole was small, the speaker says something more nuanced: it was not big enough to call big, but maybe not tiny either.

This is one of the most common learner questions.

Here большой is the instrumental singular feminine form of большая.

Why instrumental? Because in Russian, after быть in the past or future, a predicate adjective or noun can sometimes appear in the instrumental case, especially in more descriptive or nuanced phrasing.

So:

• Дырка была большой = The hole was big

This is normal Russian.

In modern Russian, with full-form adjectives after был / была / было / были, the instrumental is standard:

• Она была красивой
• Дом был высоким
• Погода была хорошей

So here:

• дырка = feminine singular
• therefore instrumental feminine singular = большой

A learner may expect большая, but that would not be correct in this structure.

Normally, no. After была, the full adjective is expected in the instrumental, so большой is the natural form.

Russian does sometimes use other predicate patterns, including short adjectives, but with большой the ordinary form here is:

• дырка была большой

So in this sentence, большой is the correct and expected choice.

Because they follow the preposition без, which requires the genitive case.

Dictionary forms:

• иголка → genitive singular иголки
• нитка → genitive singular нитки

So:

• без иголки и нитки = without a needle and thread

This is a very common pattern:

• без воды = without water
• без друга = without a friend
• без ручки = without a pen

Both nouns are singular because the meaning is general: you need a needle and thread, not necessarily multiple ones.

Because её is the direct object of зашить.

The speaker is talking about sewing up the hole, so the pronoun means it:

• её нельзя было зашить = it couldn’t be sewn up

Russian personal pronouns change form by case:

• она = she / it (subject form)
• её = her / it (object form)

So:

• Она была большой = It was big
• Её нельзя было зашить = It couldn’t be sewn up

Since дырка is feminine, the pronoun referring to it is also feminine.

Нельзя means:

• it is impossible
• one cannot
• it is not allowed

In this sentence, it means it was not possible.

Adding было puts the idea into the past:

• нельзя = cannot / impossible
• нельзя было = couldn’t / it was impossible

So:

• её нельзя было аккуратно зашить
  = it was impossible to sew it up neatly
  = you couldn’t sew it up neatly

This is an impersonal construction, which Russian uses very often.

Compare:

• Сейчас нельзя войти. = You can’t go in now.
• Вчера нельзя было войти. = You couldn’t go in yesterday.

Because Russian often uses impersonal constructions when the specific person is not important.

• её нельзя было аккуратно зашить literally means something like
  it was impossible to sew it up neatly

In natural English, we often translate this as:

• you couldn’t sew it up neatly
• it couldn’t be sewn up neatly

The speaker is focusing on the situation, not on a specific person.

Because зашить is a perfective verb, and it means to sew up / sew closed / mend by sewing.

The basic verb шить means to sew in a general or ongoing sense.

Here the idea is a single completed result:

• the hole needed to be sewn up
• not just sewn in general

So зашить is the natural choice.

Compare:

• Она шила платье. = She was sewing a dress.
• Она зашила дырку. = She sewed up the hole.

Аккуратно means:

• neatly
• carefully
• tidily

So the sentence is not just saying the hole couldn’t be sewn up at all. It says it couldn’t be sewn up neatly.

That adds an important nuance:

• maybe you could do a rough, messy repair in some other way
• but without a needle and thread, you couldn’t mend it properly

Но means but.

The sentence sets up a contrast:

• Дырка была не то чтобы большой
  = The hole wasn’t exactly big
• но без иголки и нитки её нельзя было аккуратно зашить
  = but without a needle and thread, it couldn’t be neatly sewn up

So the idea is:

• the hole was not very large,
• but it still needed proper tools to fix neatly.

Historically, иголка is related to a diminutive form, but in modern everyday Russian it is very often the normal word for a sewing needle.

So in this sentence:

• без иголки и нитки

sounds completely natural and idiomatic.

A learner may know игла, but that word is broader and can also mean things like:

• a needle in general
• a pine needle
• a syringe needle
• a record player needle, depending on context

For ordinary sewing, иголка is extremely common.

It breaks down like this:

• Дырка была не то чтобы большой
  = The hole wasn’t exactly big

• но
  = but

• без иголки и нитки
  = without a needle and thread

• её нельзя было аккуратно зашить
  = it couldn’t be sewn up neatly

A more literal English rendering would be:

• The hole was not exactly big, but without a needle and thread it was impossible to sew it up neatly.

A more natural English version might be:

• The hole wasn’t very big, but without a needle and thread you couldn’t mend it neatly.

Yes, it sounds natural.

It has a conversational, idiomatic feel because of не то чтобы, which is very common in spoken and written Russian when you want to be nuanced rather than blunt.

The whole sentence sounds like something a native speaker might naturally say when describing a small tear or hole in fabric.