This paper investigates the strong relationship between syntax and semantics or the aspects of the syntactico-semantic interface which are quite important for a satisfactory analysis of linguistic constructions. This is achieved through highlighting the correlation between the experiencer role and its case marking when it is in the nominative and the accusative cases. Case marking represents a pivotal issue in Arabic which has three cases; the nominative, the accusative and the genitive. The scope of the current paper is confined to the assignment of the first two cases to the experiencer role. These cases are regarded as two opposing entities from a grammatical perspective, and it is one of the objectives of this paper to find out whether the difference between them is semantically grounded. The experiencer role is selected to be the focus of this study as it represents and covers a wide range of human emotional, mental and perceptual interactions.