الكرسي بنفسجي.

A common Levantine-style pronunciation would be roughly il-kursi banafsaji, though the exact pronunciation of بنفسجي can vary by region.

A few useful notes:

• الـ is usually pronounced il- or el- in Levantine, not al- the way many learners first see it in textbooks.
• كرسي is commonly pronounced kursi.
• بنفسجي may sound a little different depending on whether the speaker is Syrian, Lebanese, Palestinian, or Jordanian.

الـ is the Arabic definite article, meaning the.

So:

• كرسي = chair / a chair
• الكرسي = the chair

In Levantine speech, this الـ is usually pronounced il- or el-.

In Arabic, present-tense sentences like this usually do not use a separate word for is/am/are.

So الكرسي بنفسجي literally looks like the chair purple, but it means the chair is purple.

This is completely normal in both Standard Arabic and Levantine.
If you want to say was, will be, and so on, then Arabic uses extra words, such as كان for was.

Because here بنفسجي is the predicate of the sentence, not part of a noun phrase.

Compare these two:

• الكرسي بنفسجي = The chair is purple
• الكرسي البنفسجي = The purple chair

That difference is very important:

• In الكرسي بنفسجي, بنفسجي is describing the chair in a full sentence, so it does not take الـ.
• In الكرسي البنفسجي, البنفسجي is an adjective directly attached to الكرسي, so it does take الـ.

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

So:

• كرسي بنفسجي = a purple chair
• literally: chair purple

This is the normal order in both Standard Arabic and Levantine.

كرسي is masculine, so the adjective appears in the masculine form بنفسجي.

If the noun were feminine, the adjective would usually be feminine too. For example:

• الطاولة بنفسجية = The table is purple

So yes, the adjective has to agree with the noun in gender.

The structure is natural and understandable in both.

Why learners notice this:

• The writing looks very close to Standard Arabic.
• The pronunciation in Levantine is different, especially for the definite article and sometimes for the color word.

So a Levantine speaker can absolutely say this, but they may pronounce it in a clearly dialectal way.

Not for Levantine.

In spoken Levantine, you do not add the formal case endings that appear in fully vocalized Standard Arabic grammar. You can simply say:

الكرسي بنفسجي

That is exactly what learners should focus on for everyday speech. Formal case endings belong to Standard Arabic, not normal Levantine conversation.