الدليل واضح والتلميح مهم.

In Arabic, the present-tense verb to be is usually not stated in simple sentences like this.

So:

• الدليل واضح = The evidence is clear
• التلميح مهم = The hint is important

Literally, Arabic often looks like the evidence clear and the hint important, but the meaning naturally includes is.

If you wanted the past tense, you would usually add كان:

• كان الدليل واضحًا = The evidence was clear

It is a nominal sentence structure, which is very common in Arabic.

Each part has:

• a subject/topic (مبتدأ)
• a predicate/comment (خبر)

So the sentence breaks down like this:

• الدليل = the subject
• واضح = the predicate
• التلميح = the subject of the second clause
• مهم = the predicate of the second clause

So really this is two nominal clauses joined by و:

• الدليل واضح
• والتلميح مهم

Because here they are predicates, not adjectives directly modifying a noun.

Compare:

• الدليل واضح = The evidence is clear
• الدليل الواضح = the clear evidence

That is a very important difference.

In your sentence:

• الدليل is definite: the evidence
• واضح is saying something about it: is clear

So واضح does not take الـ here.

The same applies to:

• التلميح مهم = The hint is important
• التلميح المهم = the important hint

They look similar, but they do different jobs.

• الدليل واضح = a full sentence: The evidence is clear
• الدليل الواضح = a noun phrase: the clear evidence

Why?

Because in Arabic, when an adjective modifies a noun directly, it usually matches it in definiteness:

• definite noun + definite adjective
• indefinite noun + indefinite adjective

So:

• دليل واضح = clear evidence / a clear proof
• الدليل الواضح = the clear evidence

But when the second word is the predicate of a sentence, it does not match like that:

• الدليل واضح = The evidence is clear

Because و meaning and is a clitic in Arabic: it attaches directly to the next word.

So Arabic writes:

• والتلميح

not:

• و التلميح

This is normal not only for و, but also for some other short particles in Arabic.

Although both words are written with الـ, the pronunciation changes because د and ت are sun letters.

So:

• الدليل is pronounced ad-dalīl
• التلميح is pronounced at-talmīḥ

What happens is that the l sound of الـ is not pronounced before a sun letter, and the next consonant is doubled.

So the spelling stays:

• الدليل
• التلميح

but the pronunciation is:

• ad-dalīl
• at-talmīḥ

A fully vowelled version would typically be:

الدليلُ واضحٌ والتلميحُ مهمٌّ

This shows the usual case endings for a simple nominal sentence:

• الدليلُ = nominative
• واضحٌ = nominative
• التلميحُ = nominative
• مهمٌّ = nominative

In this kind of sentence, both the subject and the predicate are normally in the nominative.

In everyday writing, these short vowels are usually omitted, which is why you normally see:

الدليل واضح والتلميح مهم

Because in fully marked Arabic, the final م has a shadda, which means the consonant is doubled in pronunciation.

So the fuller form is:

• مهمّ = muhimm

In ordinary unvowelled writing, the shadda is often left out, so you may simply see:

• مهم

But the intended pronunciation is still muhimm, not muhim.

Because that would mean something different.

• الدليل واضح ومهم = The evidence is clear and important

In that sentence, both واضح and مهم describe الدليل.

But your original sentence has two different subjects:

• الدليل is clear
• التلميح is important

So Arabic repeats the second subject to make that clear:

• الدليل واضح والتلميح مهم

Yes. Predicates like these normally agree with the subject in gender and number.

In your sentence:

• الدليل is masculine singular
• واضح is masculine singular

and:

• التلميح is masculine singular
• مهم is masculine singular

If the subject were feminine, the predicate would change, for example:

• الفكرة واضحة = The idea is clear
• الإشارة مهمة = The signal/hint is important

So agreement still matters, even though these are predicates rather than attributive adjectives.

Both ways are fine conceptually.

It is usually treated as one sentence made of two coordinated clauses:

• الدليل واضح
• والتلميح مهم

English does the same thing:

• The evidence is clear, and the hint is important.

So it is one combined sentence, but grammatically it contains two simple statements joined by and.