الخطة سيئة.

In Arabic, present-tense sentences like The plan is bad usually do not need a verb like is.

So:

• الخطة = the plan
• سيئة = bad
• Together: الخطة سيئة = The plan is bad

This is called a nominal sentence in Arabic.
If you wanted the past or future, then Arabic would use other words or structures, but in the present tense, the is/are idea is usually just understood.

A careful pronunciation would be something like:

• الخطة → il-khiTTa or el-khiTTeh
• سيئة → sayyiʔa in careful/formal reading

So the whole sentence can sound roughly like:

• il-khiTTeh sayyiʔa

A few notes:

• The خ is a throaty sound, like the ch in German Bach or Scottish loch
• The ط is a heavy/emphatic t
• The ء in سيئة is a glottal stop, like the break in uh-oh

In everyday Levantine speech, this exact adjective can sound a bit formal. A more natural colloquial version is often:

• الخطة مو منيحة
• الخطة مش منيحة

Both mean the same thing.

ال is the Arabic definite article, meaning the.

So:

• خطة = a plan / plan
• الخطة = the plan

In Levantine, ال is often pronounced el- or il-, depending on the speaker and region.

Here, because خ is not a sun letter, the l sound is pronounced clearly:

• الخطة → el-khiTTeh / il-khiTTeh

Because in Arabic, adjectives usually come after the noun they describe.

So Arabic word order is:

• noun + adjective

Here:

• الخطة = the plan
• سيئة = bad

So literally it is:

• the plan bad

This is normal Arabic structure.

Because خطة is a feminine noun, and Arabic adjectives must agree with the noun they describe.

So since خطة is feminine, the adjective must also be feminine:

• خطة سيئة = a bad plan
• الخطة سيئة = the plan is bad

If the noun were masculine, the adjective would be masculine too.

For example:

• الاقتراح سيئ = the suggestion is bad

So the feminine form here is required by grammar.

A big clue is the ending ة (called taa marbuuTa).

Many Arabic nouns ending in ة are feminine, including خطة.

So:

• خطة = feminine noun
• therefore its adjective must also be feminine:
  • سيئة

This ending is one of the most useful signals for learners, although not every feminine noun has it, and not every word with similar spelling behaves exactly the same way.

The word سيئة has two things near the end that often confuse learners:

• ء = hamza
• ة = taa marbuuTa

So سيئة is not just a simple ending. In careful reading, it is pronounced roughly:

• sa-yyi-ʔa

The hamza creates a little break or catch in the voice, and the final ة marks the feminine form.

In slower, more formal pronunciation, that glottal stop is clearer. In casual speech, some speakers may smooth it out somewhat.

It is understandable, but it sounds more formal or Standard Arabic-like than everyday Levantine conversation.

In natural spoken Levantine, people often prefer:

• الخطة مو منيحة
• الخطة مش منيحة

These are more colloquial ways to say The plan is bad.

So:

• الخطة سيئة = correct, clear, somewhat formal
• الخطة مو منيحة / مش منيحة = more everyday Levantine

Actually, in Arabic, when a noun is definite, its adjective is usually definite too.

So in very careful Standard Arabic writing, you would often expect:

• الخطة السيئة

But that phrase usually means the bad plan as a noun phrase, not a full sentence.

There is an important difference:

• الخطة السيئة = the bad plan
• الخطة سيئة = the plan is bad

So in your sentence, سيئة is functioning as the predicate of the sentence, not just as an adjective inside a noun phrase. That is why it appears without ال.

This is a very important distinction:

• الخطة سيئة = The plan is bad
• الخطة السيئة = the bad plan

In the first one:

• سيئة is the predicate
• the sentence is complete

In the second one:

• السيئة is an adjective describing الخطة
• together they form one noun phrase, not a full statement by themselves

So the presence or absence of ال on the adjective changes the structure and meaning.

Yes, if you want to make it negative in Levantine.

For example:

• الخطة مو سيئة = The plan is not bad
• الخطة مش سيئة = The plan is not bad

Both مو and مش are used in Levantine, though usage depends on region and speaker.

In very natural colloquial speech, people might also prefer:

• الخطة مو منيحة
• الخطة مش منيحة

and for the negative:

• الخطة مو منيحة كتير or other similar expressions depending on what exactly they want to say.

The sentence itself is mostly shared with Standard Arabic, especially in writing. What makes it feel more Levantine is mainly:

• the pronunciation
• whether you choose a more colloquial adjective like منيحة
• regional choices like مو vs مش

So the written form الخطة سيئة is not strongly dialect-specific. It is something a Levantine speaker would understand easily, but in everyday spoken Levantine they may choose a more colloquial wording.