تسرب الهواء كبير للغاية.

Here, تسرب is a noun, specifically a verbal noun (maṣdar), meaning leakage / seepage / a leak.

Without vowel marks, Arabic spelling can sometimes look ambiguous. But the structure makes it clear here:

• تسرب الهواء = one noun phrase
• كبير للغاية = the predicate

If it were a verb, تسرّب الهواءُ, the meaning would be more like the air leaked.

This is an iḍāfa construction, often called the genitive or possessive construction.

Arabic commonly expresses X of Y by putting two nouns together:

• تسرب = leakage
• الهواء = the air / air

So تسرب الهواء literally means leakage of air or air leakage.

In an iḍāfa:

• the first noun comes first
• the second noun explains what it is related to
• there is no word like of

Arabic usually does not use a separate word for present-tense is / am / are.

So:

• تسرب الهواء = the subject
• كبير للغاية = the predicate

Together, they mean The air leak is extremely large, even though there is no written word for is.

If you wanted past tense, Arabic could use كان:

• كان تسرب الهواء كبيرًا = The air leak was large

Because كبير is a predicate adjective, not an adjective directly attached to the noun inside the same noun phrase.

Compare:

• تسرب الهواء كبير = The air leak is big
• التسرب الكبير للهواء = the big air leak

In Arabic, predicate adjectives are normally indefinite, so كبير appears without ال.

Because تسرب is grammatically masculine singular, and كبير agrees with it.

A common beginner mistake is to think a word is feminine because it starts with ت. But Arabic feminine marking is usually shown by a final ة, not by an initial ت.

So:

• تسرب = masculine
• therefore كبير = masculine singular

الهواء means the air or air in a general, definite sense.

In an iḍāfa, if the second noun is definite, the whole phrase becomes definite too. So تسرب الهواء is understood as a definite phrase: the air leakage or the leakage of the air.

Also, Arabic often uses ال in places where English may or may not use the, so article usage does not always match English exactly.

للغاية means extremely, to a very great extent, or to the utmost degree.

So:

• كبير للغاية = extremely large / very large

It is a common formal intensifier in Modern Standard Arabic.

They are very similar in meaning, but not identical in tone.

• كبير جدًا = very big
• كبير للغاية = extremely big / very big, often a bit more formal or emphatic

In Modern Standard Arabic, للغاية often sounds a little more polished or written than جدًا.

It can mean more than just physical size.

With something like تسرب (leakage), كبير can suggest:

• large in amount
• extensive
• significant
• sometimes even serious

So depending on context, English might render it as large, major, or serious.

A fully vowelled version is:

تَسَرُّبُ الْهَوَاءِ كَبِيرٌ لِلْغَايَةِ

A careful pronunciation would be approximately:

tasarrubu l-hawā’i kabīrun lil-ghāyati

In normal speech, many speakers drop the final case endings, so you may hear something closer to:

tasarrub al-hawā’ kabīr lil-ghāya

Yes. It is grammatical and natural in MSA, especially in a formal or report-like style.

Depending on context, Arabic might also use other phrasings, such as:

هناك تسرّب كبير للهواء

This has more of a There is a major air leak feel. But تسرب الهواء كبير للغاية is perfectly acceptable.