الفرق مهم.

• الفرق = the difference
• مهم = important

So the sentence literally reads the difference important, which in natural English is The difference is important.

In Arabic, the verb to be is usually not written in the present tense when making simple statements.

So:

• الفرق مهم = The difference is important

But in other tenses, Arabic does use a verb:

• كان الفرق مهمًا = The difference was important
• سيكون الفرق مهمًا = The difference will be important

This is a very common feature of Arabic nominal sentences.

الـ is the definite article, meaning the.

• الفرق = the difference
• فرق = a difference or just difference depending on context

The adjective/predicate مهم does not have الـ here because it is not being used as an attributive adjective inside a noun phrase like the important difference. Instead, it is the predicate of the sentence:

• الفرق مهم = The difference is important

Compare that with:

• الفرق المهم = the important difference

That second example is not a full sentence by itself in the same way; it is a noun phrase.

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

So grammatically:

• الفرق = the subject/topic
• مهم = the predicate/comment

Arabic often uses adjectives this way in nominal sentences:

• الجو جميل = The weather is nice
• الكتاب جديد = The book is new
• الفرق مهم = The difference is important

The most basic and neutral order in this kind of Arabic sentence is:

• subject + predicate

So:

• الفرق مهم = The difference is important

You may sometimes see the predicate first for emphasis or style, but the basic learner-friendly order is the one in your sentence.

In fully vocalized, formal grammar, yes:

• الفرقُ مهمٌّ

The endings are:

• الفرقُ with -u because it is the subject
• مهمٌّ with -un because it is the predicate and indefinite

However, in normal modern written Arabic, short case endings are usually not written, so you normally just see:

• الفرق مهم

That is completely standard.

A careful pronunciation is approximately:

• al-farqu muhimmun

In everyday reading without case endings, learners often say something like:

• al-farq muhimm

A few helpful notes:

• الفرق is pronounced roughly al-farq
• مهم is pronounced roughly mu-himm
• The هـ in مهم is a real h sound
• The doubled consonant in مهم means the m is held slightly longer: mu-himm

الفرق comes from the root ف ر ق which is connected with meanings like:

• separating
• distinguishing
• difference

Related words include:

• فرق = difference
• يفرق = he distinguishes / separates
• تفريق = separation
• فارق = difference; also he left/separated from, depending on form and context

Knowing the root can help you recognize related vocabulary.

Yes, depending on context, فرق and related forms can have several meanings connected to separation or distinction.

But in a simple sentence like الفرق مهم, the most natural meaning is:

• The difference is important

Context is what decides the best translation.

الفرق is a masculine noun, so the predicate adjective appears in the masculine singular form:

• الفرق مهم

If the subject were feminine singular, the adjective would usually also be feminine:

• الفكرة مهمة = The idea is important

So yes, Arabic adjectives generally agree in gender and number with the noun they describe or refer back to.

The meaning is the same.

• الفرق مهم = normal unvocalized modern writing
• الفرق مهمٌّ = fully vocalized form showing grammar more explicitly

The second version includes the case ending and the shadda on the second م, which helps show the exact pronunciation:

• muhimmun

In most real-world texts, you will usually see the shorter written form without full vowel marks.

You could say:

• فرقٌ مهمٌّ

That means A difference is important or A difference matters, depending on context.

Compare:

• الفرق مهم = The difference is important
• فرق مهم = an important difference if read as a noun phrase without case endings
• فرقٌ مهمٌّ = A difference is important in a fully vocalized sentence

Without vowels, Arabic can sometimes look ambiguous, so context matters.

This is an important distinction:

• الفرق مهم = The difference is important
  This is a full sentence.

• فرق مهم = an important difference
  This is usually just a noun phrase, not a full sentence.

Why? Because when a noun and adjective are both indefinite, they usually go together as one phrase:

• كتاب جديد = a new book
• فرق مهم = an important difference

But when the first word is definite and the second is indefinite, that often makes a full sentence:

• الكتاب جديد = The book is new
• الفرق مهم = The difference is important