Learn Arabic (Modern Standard): المطعم مغلق.

In Arabic, simple sentences that describe something (called nominal sentences) do not use a verb for "is" or "are" in the present tense. By simply putting the subject المطعم (the restaurant) right next to the describing word مغلق (closed), the "is" is automatically understood.

Why does المطعم have "al-" (the) but مغلق does not?

This is the secret to making a descriptive sentence! The subject gets "al-" to make it specific (The restaurant), but the describing word (the predicate) must stay indefinite, meaning no "al-". If both words had "al-", it would just mean "the closed restaurant" instead of making a full sentence.

Would مغلق change if we were talking about a feminine place?

Yes! Describing words must always match the gender of the noun. Because المطعم is masculine, مغلق is masculine. If we wanted to say "The library is closed", we would use the feminine word المكتبة and add a feminine taa marbuuTa ending to the adjective: المكتبة مغلقة.

How do I know what vowel sound goes at the very end of مغلق?

If you are reading with full formal grammar endings, the predicate of a sentence takes an "un" sound (tanween damma), so it would be "mughlaqun". However, because it is the last word in the sentence, you use the pausing rule and just stop on the consonant: "mughlaq".