You are right. It is correct. whenever there is a word before the noun that starts with الـ (maa'refah)* that means it is an adjective. If you you say السفير العربي = the listener already knows about this information (that he is an arab) But if you say السفير عربي = the listener doesn't know this information (that he is an arab) Ex: الفتاة الجميلة = the beautiful girl الفتاة جميلة = the girl is beautiful as you can see here جميلة without الـ (nakerah)** and again in your example عربي without الـ that means you are telling a new information that the listener doesn't know about. PS: * Maa'refah means known (with الـ ) ** Nakerah means unknown (without الـ)