This research presents for the in Arabic with a complete explanation that handles it from all sides, starting with its grammatical particularities that run against the customary principles in the Arabic, in order to achieve rhetorical goals and explanatory purposes with relevant and suitable examples, and required explanation for each particular, while also passing by its analytical rulings that vary between nominative and accusative cases, and finally reaching to its eloquence and usages. Ḍamīru'ş-şaʾn has many particulars that differentiate it from other pronouns by expressive and eloquent way that raises its value and situation. So, the ancient Arabs used to use it extensively in poetry and prose, as it is clearly used in many verses of the Holy Qur'an.