الفيلم مضحك.

Because Arabic usually does not use a present-tense copula in sentences like this.

So الفيلم مضحك literally looks like the movie funny, but in natural English it means The movie is funny.

This kind of sentence is called a nominal sentence in Arabic.

• Present: الفيلم مضحك = The movie is funny
• Past: كان الفيلم مضحكًا = The movie was funny

So the missing is is completely normal.

الـ is the Arabic definite article, equivalent to the in English.

So:

• فيلم = a movie / movie
• الفيلم = the movie

In this sentence, the speaker is talking about a specific movie, so الفيلم is definite.

Because مضحك is the predicate of the sentence, not an attributive adjective inside a noun phrase.

Here:

• الفيلم مضحك = The movie is funny

But compare:

• الفيلم المضحك = the funny movie

That is a very important difference:

• الفيلم مضحك → a full sentence
• الفيلم المضحك → a noun phrase

So in your sentence, مضحك stays indefinite.

Yes, in meaning and function here, it works like an adjective: funny, amusing.

More precisely, it is also the predicate of the nominal sentence.

It can also appear as a regular adjective after a noun:

• فيلم مضحك = a funny movie
• الفيلم المضحك = the funny movie

So yes, you can think of it as an adjective, but in this sentence it is specifically the predicate adjective.

Because فيلم is a masculine singular noun, and the predicate matches it.

So:

• الفيلم مضحك = masculine singular
• القصة مضحكة = feminine singular

If the noun were feminine, the form would normally change.

With full case endings, it would usually be written:

الفيلمُ مُضحِكٌ

Here:

• الفيلمُ ends in -u
• مُضحِكٌ ends in -un

In normal everyday Arabic writing, these short vowels are usually not written, which is why you usually see:

الفيلم مضحك

It is pronounced approximately al-fīlm in pause, or al-fīlmu with full case ending.

A few helpful points:

• الـ is pronounced al-
• ف is a moon letter, so the l sound is pronounced clearly
• ي here gives a long ī sound

So the word sounds roughly like al-feelm.

It is pronounced approximately muḍḥik in pause, or muḍḥikun with full ending.

Two letters may feel unusual to English speakers:

• ض = a heavy/emphatic d sound
• ح = a voiceless deep h sound, produced farther back than English h

So the word is not like a simple English mud-hik. The middle consonants are more Arabic-sounding and stronger.

The root is ض ح ك, which is connected with laughing.

So مضحك has the sense of causing laughter or making someone laugh, which is why it means funny or amusing.

Knowing the root can help you connect it to related words, such as:

• ضحك = he laughed / laughter-related root idea
• يضحك = he laughs
• مضحك = funny / laugh-inducing

Yes, very common.

Arabic often uses this exact pattern:

definite noun + predicate

For example:

• الجو جميل = The weather is nice
• الكتاب مفيد = The book is useful
• الفيلم مضحك = The movie is funny

So this sentence is a very standard and useful pattern to learn early.