هذا الموسم ممتع.

هذا means this and is the masculine singular demonstrative in Arabic.

It comes first here because the sentence is structured as this season [is] enjoyable. Since الموسم is a masculine singular noun, هذا is the correct form.

If the noun were feminine singular, you would usually use هذه instead.

In Arabic, sentences in the present tense often do not use a separate word for is / am / are.

So:

• هذا الموسم ممتع
  literally looks like: this season enjoyable

But it naturally means:

• This season is enjoyable

This is completely normal in Arabic. If you wanted a past or future meaning, then Arabic would use other forms.

In fully vocalized formal Arabic, case endings can appear, so you might see:

• هذا الموسمُ ممتعٌ

Here, الموسمُ has a ḍammah because it is the subject of a nominal sentence, and ممتعٌ also takes a ḍammah because it is the predicate.

However, in normal everyday writing, short vowel case endings are usually not written, so learners commonly see:

• هذا الموسم ممتع

That is the standard unvocalized spelling.

الموسم means the season, so it has the definite article الـ.

But ممتع is an adjective used here as the predicate, meaning enjoyable. In this kind of sentence, the predicate usually does not take الـ unless you specifically mean something like the enjoyable one.

So:

• الموسم = the season
• ممتع = enjoyable

This is why the sentence is not هذا الموسم الممتع if you mean This season is enjoyable.

Note that هذا الموسم الممتع would more naturally mean this enjoyable season.

It is an adjective in meaning, but in this sentence it functions as the predicate of a nominal sentence.

Arabic grammarians would analyze the sentence roughly like this:

• هذا الموسم = the topic / subject part
• ممتع = the predicate / comment about it

So ممتع describes the season, but grammatically it is the second main part of the sentence, not just an adjective directly attached to the noun.

That is different from:

• هذا الموسم الممتع = this enjoyable season

In that phrase, الممتع is a direct adjective modifying الموسم.

Because الموسم is a masculine noun, and adjectives in Arabic must agree with the noun they describe in gender.

So:

• masculine singular: ممتع
• feminine singular: ممتعة

Since الموسم is masculine, the correct form is ممتع.

There are two kinds of agreement happening:

1. هذا agrees with الموسم

   • both are masculine singular

2. ممتع also agrees with الموسم

   • masculine singular

So all the relevant parts match in gender and number.

This kind of agreement is very important in Arabic.

A careful pronunciation is roughly:

• hādhā al-mawsim mumtiʿ

A few notes:

• هذا = hādhā
• الموسم = al-mawsim
• ممتع = mumtiʿ

The last consonant in ممتع is ع (ʿayn), which has no exact English equivalent. Learners often need practice with that sound.

If fully vowelled, you may hear or see:

• hādhā al-mawsimu mumtiʿun

But in normal speech and writing, those final case vowels are often not emphasized.

This is a nominal sentence.

A nominal sentence usually begins with a noun, pronoun, or noun phrase rather than a verb. It often has two parts:

• the thing being talked about
• what is being said about it

Here:

• هذا الموسم = what you are talking about
• ممتع = what you say about it

So this is a very common and basic Arabic sentence pattern.

Yes, but the meaning changes slightly.

• هذا الموسم ممتع = This season is enjoyable
• هذا موسم ممتع = This is an enjoyable season

In the first sentence, الموسم is definite: the season.
In the second, موسم is indefinite: a season.

So both are grammatical, but they do not mean exactly the same thing.

In Modern Standard Arabic, هذا الموسم is the normal way to say this season.

So the demonstrative usually comes before the noun in this structure:

• هذا الكتاب = this book
• هذا الموسم = this season

Learners may later notice other patterns in spoken dialects, but for MSA, هذا الموسم is the standard form to learn.