هذا خطأ.

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

So هذا خطأ literally looks like this error/mistake, but it means this is a mistake or this is wrong.

This kind of sentence is called a nominal sentence. Arabic often just puts:

• the subject first: هذا
• then the description or identification: خطأ

If you wanted past or future, Arabic would use a verb, but in the present it is normally omitted.

هذا is the masculine singular demonstrative pronoun, meaning this.

It is used for:

• a masculine singular noun
• or very often for a whole situation, statement, or idea, similar to English this

So in هذا خطأ, هذا can mean:

• this thing is a mistake
• this is wrong
• this is an error

هذا is the masculine singular form of this.
هذه is the feminine singular form.

Examples:

• هذا كتاب = this is a book / this book
• هذه سيارة = this is a car / this car

In هذا خطأ, Arabic uses the masculine form because خطأ is masculine, and also because هذا is often the default when referring to a general situation or statement.

Because it is being used as the predicate of the sentence, and predicates in Arabic are often indefinite.

So:

• هذا خطأ = this is a mistake / this is wrong
• هذا الخطأ would usually mean this is the mistake, which is much more specific

Using خطأ without ال gives the normal meaning here.

It is primarily a noun meaning mistake or error.

So هذا خطأ is literally something like:

• this is an error
• this is a mistake

But in natural English, that often becomes:

• this is wrong

So even though English may use an adjective (wrong), Arabic is using a noun.

It is pronounced approximately kha-taʼ.

A more careful breakdown:

• خ = a rough kh sound, like the ch in German Bach or Scottish loch
• ط = an emphatic t
• final ء = a glottal stop, a catch in the throat

So the word ends with a little stop: kha-taʼ, not just khata.

That is hamza (ء), which represents a glottal stop.

In this word, it is an actual consonant, so it should be pronounced.
That means خطأ is not the same as a word ending in a simple vowel.

This is an important part of the word’s pronunciation.

In fully vocalized formal Arabic, yes, you could write:

هٰذا خَطَأٌ

The ـٌ marks tanwīn ḍamm and shows that خطأ is indefinite and nominative.

But in normal Arabic writing, short vowels and case endings are usually not written, so you normally just see:

هذا خطأ

Also, in pause at the end of a sentence, speakers often do not pronounce the final case ending clearly anyway.

This is the normal order for a simple nominal sentence:

1. هذا = the topic / subject
2. خطأ = the predicate

So the structure is very natural:

• هذا جميل = this is beautiful
• هذا صحيح = this is correct
• هذا خطأ = this is wrong / a mistake

Arabic can change word order for style or emphasis, but this version is the most straightforward.

Normally, no. That would sound unnatural here.

The sentence هذا خطأ is already complete and correct.

Sometimes Arabic uses هو as a separating pronoun in more specific structures, such as:

• هذا هو الحل = this is the solution

But for this is wrong / this is a mistake, the simple form هذا خطأ is the normal one.

It is perfectly good Modern Standard Arabic and is also very understandable in many everyday contexts.

However, in spoken dialects, people may use other common expressions depending on the country. Still, هذا خطأ is a very standard and useful MSA sentence.

Yes.

That is a very common thing in Arabic. The noun خطأ can naturally correspond to:

• a mistake
• an error
• wrong

So depending on context, هذا خطأ may be translated as:

• This is a mistake.
• This is an error.
• This is wrong.

A common way is:

هذا خطأ كبير = this is a big mistake
or
هذا خطأ فادح = this is a serious/grave mistake

You might also say:

• هذا غير صحيح = this is not correct
• هذا أمر خاطئ = this is a wrong thing / this is incorrect

So هذا خطأ is a basic pattern that can be expanded easily.

Then you would use ذلك for that:

ذلك خطأ

So:

• هذا خطأ = this is a mistake
• ذلك خطأ = that is a mistake

This is a useful pair to learn together.