الأصل واضح.

In Arabic, the present-tense verb to be is usually omitted in simple sentences like this. So Arabic says, literally, the origin/principle clear, where English needs is: the origin/principle is clear.

This kind of sentence is very common in Arabic. If you wanted the past tense, you would normally add كان: كان الأصل واضحًا = the origin/principle was clear.

This is a nominal sentence.

• الأصل is the subject/topic, traditionally called المبتدأ
• واضح is the predicate/comment, traditionally called الخبر

So the sentence structure is:

الأصل = the thing being talked about
واضح = what is being said about it

In fully vocalized Arabic, it is:

الأصلُ واضحٌ

Because here واضح is not an attributive adjective inside a noun phrase; it is the predicate of the whole sentence.

Compare:

• الأصلُ واضحٌ = The origin/principle is clear
• الأصلُ الواضحُ = the clear origin/principle

In the second example, الواضح directly modifies الأصل, so it matches it in definiteness. In your sentence, واضح is telling us something about الأصل, so it stays indefinite.

الـ is the definite article, like English the.

So أصل is origin / root / principle, while الأصل is the origin / the principle / the basic rule, depending on context.

Arabic also uses the definite article in some general statements where English may sound more natural without the. So الأصل can sometimes mean something like the basic principle or the default rule, not only one specific physical origin.

In normal Arabic writing, short vowels are usually not written. Fully vocalized, this sentence is:

الأصلُ واضحٌ

The endings are important in formal grammar:

• الأصلُ ends in -u because it is the subject
• واضحٌ ends in -un because it is an indefinite predicate in the nominative

In careful reading, you could say:

al-ʾaṣlu wāḍiḥun

But if you stop at the end of the sentence, the final short ending is usually not pronounced, so you often hear:

al-ʾaṣlu wāḍiḥ

Because the word is made of two parts:

• الـ = the definite article
• أصل = the noun itself

So:

ال + أصل = الأصل

The second alif carries the noun’s own hamza. That is why the spelling may look a little unusual at first.

A careful pronunciation is:

al-ʾaṣl
or, with the full case ending, al-ʾaṣlu

A few notes:

• The ل in الـ is pronounced normally here
• The أ is a real hamza, a glottal stop
• The ص is an emphatic s
• The end has a consonant cluster: ṣl

If the cluster feels hard, the fully vocalized form aṣ-lu is often easier for learners than the pause form aṣl.

It is pronounced:

wāḍiḥ

A rough breakdown:

• wā = like waa, with a long ā
• ḍ = an emphatic, heavier version of d
• i = short i
• ḥ = a voiceless sound from deeper in the throat than English h

A very rough English-friendly approximation is WAA-dih, but that does not fully capture the Arabic ض and ح.

Yes. Since الأصل is masculine singular, واضح is also masculine singular.

This is normal when an adjective-like word is used as a predicate. If the subject were feminine singular, you would usually expect:

... واضحة

So agreement still matters, even though واضح is functioning as the predicate of the sentence rather than as a directly attached adjective.