This is the 5111th most frequent Arabic word.
الوثائقي
Documentary.
In this sentence, the term "الوثائقي" is used as an adjective modifying the noun "الفيلم" (the film), describing its genre as a documentary.
شاهدنا الفيلم الوثائقي عن الحياة البرية في إفريقيا.
We watched the documentary about wildlife in Africa.
Here, "الوثائقية" (the documentary), which is the feminine form of the adjective, is used to describe "الكتب" (books), indicating their factual documentary nature.
يميل أبي إلى قراءة الكتب الوثائقية ذات المعلومات الغنية.
My father tends to read documentary books with rich information.
In this example, "وثائقي" is used as a noun referring to the genre or type of TV program.