الراحة مهمة.

A careful MSA pronunciation is:

ar-rāḥatu muhimmatun
or, in pause (which is how people often say it aloud):
ar-rāḥa muhimma

A few notes:

• الراحة begins with الـ (al-), but because ر is a sun letter, the l sound assimilates, so you say ar-, not al-.
• ح in راحة is a deeper h sound, made in the throat.
• The final ة is usually pronounced -a when pausing, but in full grammatical pronunciation it can sound like -atun / -atun depending on case and tanwīn.

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

So:

• راحة = rest / comfort / relaxation
• الراحة = the rest / rest in a general definite sense

In many Arabic sentences, a definite noun like this can represent a general idea, so الراحة can mean something like rest as a concept, not necessarily one specific rest.

Because Arabic usually does not use a present-tense verb to be in simple sentences like this.

So:

• الراحة مهمة literally looks like rest important
• but it means Rest is important

This is completely normal in Arabic. In the present tense, Arabic often leaves out is / am / are.

If you wanted the past tense, then Arabic would use a verb, for example:

• كانت الراحة مهمة = Rest was important

Because it describes الراحة, and الراحة is a feminine noun.

In Arabic, adjectives must agree with the noun they describe in:

• gender
• number
• definiteness

So:

• masculine: مهم
• feminine: مهمة

Since الراحة is feminine, the adjective/predicate must also be feminine:

• الراحة مهمة

A big clue is the ending ة (called tāʾ marbūṭa), which very often marks feminine nouns.

So:

• راحة ends in ة
• therefore it is typically feminine

This is not an absolute rule for every word in Arabic, but it is one of the most common patterns learners use.

Because in this sentence مهمة is the predicate, not an adjective directly attached to a noun phrase.

This is an example of a nominal sentence:

• الراحة = the subject/topic
• مهمة = the predicate/comment

In Arabic, when a simple sentence means X is Y, the first noun is often definite and the second part is often indefinite.

So:

• الراحة مهمة = Rest is important

If you said الراحة المهمة, that would usually mean the important rest, which is a noun phrase, not a full sentence.

It is originally an adjective meaning important, but here it functions as the predicate of the sentence.

So grammatically, it is the word describing the subject:

• الراحة = rest
• مهمة = important

In English terms, you can think of it as a predicate adjective in Rest is important.

This is a nominal sentence (جملة اسمية), meaning a sentence that begins with a noun rather than a verb.

Its two main parts are:

• المبتدأ (mubtadaʾ) = the subject/topic → الراحة
• الخبر (khabar) = the predicate/comment → مهمة

So the structure is:

• الراحة = what we are talking about
• مهمة = what we say about it

In full formal Arabic with case endings, it would be:

الرّاحةُ مهمّةٌ

Why?

• الرّاحةُ has ḍamma because it is the mubtadaʾ (subject of a nominal sentence), so it is nominative.
• مهمّةٌ also has ḍamma + tanwīn because it is the khabar (predicate), also nominative and indefinite.

In everyday writing, short vowels are usually omitted, so you normally see:

الراحة مهمة

Not only rest. Depending on context, الراحة can mean:

• rest
• comfort
• relaxation
• ease

Arabic words often cover a wider range than a single English word. In this sentence, the exact English translation depends on context, but the general idea is that rest/comfort/relaxation is important.

Yes, but the basic sentence الراحة مهمة is the most straightforward and neutral.

This order puts the topic first:

• الراحة مهمة = Rest is important

In some contexts, Arabic can shift emphasis, but for a beginner, this is the standard pattern to focus on:

• definite noun first
• predicate second

So this is a very useful model for making simple statements in Arabic.

That letter is called tāʾ marbūṭa (ة).

In these words:

• راحة
• مهمة

It usually signals a feminine form.

Pronunciation:

• In pause, it is usually pronounced like -a
• When followed by grammatical endings or in certain grammatical constructions, it can sound like -t

So you may hear or analyze:

• راحة → rāḥa
• راحةٌ → rāḥatun
• مهمة → muhimma
• مهمةٌ → muhimmatun

Yes. That is one reason Arabic vocabulary can feel flexible in translation.

Depending on context, الراحة مهمة could naturally mean:

• Rest is important
• Comfort is important
• Relaxation is important

If the meaning has already been shown to the learner, the main grammar point is that the Arabic sentence structure stays the same regardless of which English wording fits best.