هذا معرض مؤقت.

Because Arabic often uses a nominal sentence in the present tense, with no written or spoken equivalent of is / am / are.

So:

• هذا معرض مؤقت
• literally: this temporary exhibition
• natural meaning: This is a temporary exhibition.

In the present tense, Arabic usually just puts the parts of the sentence next to each other.

If you wanted the past or future, Arabic would use a verb, for example with كان for was.

هذا means this for a masculine singular noun.

Here, the noun is معرض (exhibition), which is grammatically masculine singular, so هذا is the correct form.

Compare:

• هذا معرض = This is an exhibition / This exhibition
• هذه مدرسة = This is a school / This school

So the choice between هذا and هذه depends on the gender of the noun.

Because these two phrases mean different things.

1. هذا معرض مؤقت

This means:

• This is a temporary exhibition

Here, هذا is acting like this is, and معرض مؤقت is the predicate.

2. هذا المعرض المؤقت

This means:

• this temporary exhibition

Here, هذا is directly describing a specific noun phrase: the temporary exhibition.

So:

• هذا معرض مؤقت = a full sentence
• هذا المعرض المؤقت = a noun phrase

This is a very common point of confusion for English speakers.

Because in Arabic, adjectives usually come after the noun they describe.

So:

• معرض مؤقت = a temporary exhibition
• literally: exhibition temporary

This is the normal order in Arabic.

More examples:

• كتاب جديد = a new book
• بيت كبير = a big house

Because the adjective must agree with the noun it describes.

معرض is:

• masculine
• singular
• indefinite

So the adjective must also be:

• masculine
• singular
• indefinite

That gives us:

• معرض مؤقت

If the noun were feminine, the adjective would usually also be feminine:

• مدرسة مؤقتة = a temporary school

معرض can mean exhibition, fair, or display, depending on context.

Common uses include:

• معرض فني = art exhibition
• معرض الكتاب = book fair
• معرض سيارات = car show / car exhibition

In your sentence, معرض most naturally means exhibition.

مؤقت means temporary, not permanent, or for a limited time.

It comes from a root related to time.

For example:

• حل مؤقت = a temporary solution
• إغلاق مؤقت = temporary closure

So معرض مؤقت means an exhibition that is only there for some period, not permanently.

A careful pronunciation is roughly:

• هذا = haadha
• معرض = maʿraḍ
• مؤقت = muʾaqqat

A few notes:

• ع in معرض is a consonant that does not exist in English. Learners usually need time to get used to it.
• ض is an emphatic consonant, somewhat like a heavy d.
• In مؤقت, the ؤ represents a hamza sound, so there is a little break: mu-ʾaq-qat, not a smooth mooakat.

A simple learner-friendly approximation is:

• HAA-dha ma-rad moo-AK-kat

But that is only approximate.

Because ordinary Arabic writing usually leaves out short vowels and case endings.

So you see:

• هذا معرض مؤقت

But in fully vocalized formal Arabic, it would be:

• هٰذا مَعْرَضٌ مُؤَقَّتٌ

The final -un on both معرض and مؤقت shows that they are indefinite and nominative in this sentence.

Most everyday printed Arabic leaves those endings unwritten.

It is indefinite.

That is because:

• معرض has no ال
• مؤقت has no ال
• in full vocalization, both would normally take tanwīn: معرضٌ مؤقتٌ

So it means:

• a temporary exhibition

not

• the temporary exhibition

If you wanted the temporary exhibition, you would say:

• المعرض المؤقت

In a way, yes.

Word-for-word, هذا just means this. But in a sentence like:

• هذا معرض مؤقت

the whole sentence is understood as:

• This is a temporary exhibition

So learners often feel that هذا is behaving like this is in translation, even though Arabic grammar analyzes it differently.

That is very normal and useful for understanding.

Not as naturally as the intended meaning.

هذا معرض مؤقت most naturally means:

• This is a temporary exhibition

If you want to say:

• This exhibition is temporary

you would more naturally say:

• هذا المعرض مؤقت

Here:

• هذا المعرض = this exhibition
• مؤقت = temporary

So the presence or absence of ال changes the structure and meaning.

It is a nominal sentence made of:

1. هذا — the topic or subject-like element: this
2. معرض مؤقت — the predicate: a temporary exhibition

Inside the predicate:

• معرض = noun
• مؤقت = adjective describing that noun

So the structure is:

• هذا
  • [noun + adjective]
• This is
  • [a temporary exhibition]

That is a very common Arabic pattern.