الكذب مشكلة.

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

So:

• الكذب مشكلة
• literally: lying / falsehood — a problem
• natural English: Lying is a problem

This kind of sentence is called a nominal sentence.

They are both nouns in this sentence.

• الكذب is the subject/topic: lying or falsehood
• مشكلة is the predicate: a problem

So the structure is:

• الكذب = what we are talking about
• مشكلة = what we are saying about it

No. الكذب is a noun, not a verb.

More specifically, it is a verbal noun (often called a maṣdar), from the verb كَذَبَ = to lie.

That is why it can mean something like:

• lying
• falsehood
• dishonesty

English often uses an -ing form here, but Arabic commonly uses a verbal noun instead.

Because Arabic often uses الـ with abstract ideas and general categories.

So الكذب here does not mean one specific lie. It means lying as a general concept.

Compare the idea in English:

• Honesty is important
• Lying is a problem

Arabic often uses الـ for that kind of broad, general statement.

Because it is describing what lying is: a problem, not the problem.

So:

• الكذب مشكلة = Lying is a problem
• الكذب هو المشكلة = Lying is the problem

That small difference matters. The indefinite مشكلة gives the general meaning a problem.

In fully vowelled, formal Arabic, the sentence would be:

• الكذبُ مشكلةٌ

Both words are in the nominative case here.

So you may see them explained as:

• الكذبُ = subject/topic
• مشكلةٌ = predicate

In normal everyday writing, those short vowels are usually left out, which is why you normally see:

• الكذب مشكلة

The ة (called tāʾ marbūṭa) usually marks a word as feminine.

So مشكلة is a feminine noun meaning problem.

In this sentence, that does not change the English translation very much, but it matters for agreement in Arabic. For example, if you add an adjective, it should usually be feminine too:

• مشكلة كبيرة = a big problem

You usually would not say الكذب هو مشكلة in this simple context.

The most natural sentence is:

• الكذب مشكلة

If you add هو, it usually adds emphasis or a more specific contrast, and it often sounds more natural when the predicate is also definite:

• الكذب هو المشكلة = Lying is the problem

So for the basic meaning Lying is a problem, the version without هو is best.

Here, الـ is pronounced normally as al- because ك is a moon letter, not a sun letter.

So the l sound is kept.

In careful reading, the sentence is pronounced roughly:

• al-kadhibu mushkilatun

In pause, learners often hear something closer to:

• al-kadhib mushkila or mushkilah

The exact ending sound depends on whether the speaker is pronouncing full case endings or pausing naturally.