المصدر واضح.

A natural Egyptian pronunciation is el-maṣdar wāḍeḥ.

A few sound notes:

• الـ is usually pronounced el- in Egyptian, not al-.
• ص in مصدر is a “heavy” or emphatic s.
• ض in واضح is a “heavy” d sound.
• Final ح is a strong breathy throat sound, not the normal English h.

Because Arabic often leaves out the present-tense verb to be.

So:

• المصدر واضح literally looks like the source clear
• but it means the source is clear

This is completely normal in Arabic.
If you want past tense, you would add a verb, for example:

• المصدر كان واضح = The source was clear

It is a complete sentence.

This is called a nominal sentence in Arabic. It has:

• المصدر = the subject/topic
• واضح = the predicate/comment about the subject

So the sentence structure is basically:

• the source
  • clear

which Arabic understands as The source is clear.

Because these mean different things.

• المصدر واضح = The source is clear
  This is a full sentence.

• المصدر الواضح = the clear source
  This is just a noun phrase, not a full sentence.

In Arabic, when an adjective is part of the predicate of a sentence, it usually does not take الـ.
When an adjective directly describes a noun inside a noun phrase, it does match the noun in definiteness.

Because that is the normal order in Arabic.

Arabic usually puts:

• the noun first
• then the adjective or predicate after it

So:

• المصدر واضح = literally the source clear

This is normal both for:

1. sentences like this one
2. noun + adjective phrases such as المصدر الواضح

English often puts adjectives before nouns, but Arabic usually puts them after.

Yes. واضح agrees with المصدر in gender and number.

Here:

• المصدر is singular masculine
• so واضح is also singular masculine

If the noun were feminine, the adjective would change too:

• المعلومة واضحة = The information is clear

So the ـة ending in واضحة marks the feminine form.

Yes.

Depending on context, مصدر can mean:

• source
• origin
• in grammar, verbal noun / masdar

So if you have studied Arabic grammar before, you may already know مصدر as a grammar term.
In this sentence, the intended meaning depends on context, but the word itself has more than one use.

In Egyptian Arabic, the natural negative is:

• المصدر مش واضح = The source is not clear

Here مش is the common Egyptian way to say not with adjectives and many non-verbal sentences.

For comparison:

• المصدر واضح = The source is clear
• المصدر مش واضح = The source is not clear

It works in both.

The writing is the same:

• المصدر واضح

But in Egyptian Arabic, the pronunciation is more like:

• el-maṣdar wāḍeḥ

Also, Egyptian speech does not use the case endings you might learn in Standard Arabic.
So a learner will often see this written in a Standard-looking way, but pronounce it in an Egyptian way.

In short:

• structure: fine in both
• pronunciation: Egyptian in speech
• spelling: shared with Standard Arabic